1976 2581The Cyclic Acetals from I ,4,5,6,7,7-Hexachloronorborn-5-en-2-endo-ylalkanolsBy David 1. Davies and Adrian L. B. Gale, Department of Chemistry, King's College, Strand, London WC2R 2LSThe reaction of 1,4,5,6,7,7-hexachloronorborn-5-en-2-e~do-ylmethanol with sodium ethoxide to afford the cyclicacetal 5-endo,6,7,7,8-pentachloro-4-exo-ethoxy-3-oxatricyclo[4.2.1 .04vs]nonane is found to involve the inter-mediacy of 1,4,5,7,7-pentachloro-6-ethoxynorborn-5-en-2-endo-ylmethanol and 4-exo.5-endo.6.7.7.8- hexa-chloro-3-oxatricyclo[4.2.1 .04p8] nonane. 6-endo,7,8,8,9-Pentachloro-5-exo-ethoxy- and methoxy-4-oxatricyclo-[5.2.1 .O5l9]decane are formed from the reactions of 1.4.5.6.7.7- hexachloronorborn-5-en-2-endo-ylethanol withsodium ethoxide and methoxide. respectively.N.m.r. studies suggest that in these product cyclic acetals theconformation of the pyran ring tends towards a boat rather than a chair form.THE reaction of 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylmethanol (1A) with sodium ethoxide in ethanolicsolution gives the cyclic acetal (2A), which on treatmentwith acid affords the hemiacetal (3A); the reaction of(3A) with phosphorus pentachloride produces the chloro-ketone (4A).l This series of reactions is well documented,and a variety of cyclic acetals related to (2A) can beformed by reactions of (IA) with other sodium alk-oxides.1$2 It was subsequently reported3 that (1A) onP. E. Hoch, G. B. Stratton, and J. G. Colson, J . Org. Chem.,1969, 34, 1913.treatment with sodium methoxide afforded the cyclicacetal (2B).Surprisingly these authors did not mentionthe work of Hoch, who had investigated the abovereaction and established the structure of (2B) some fouryears ear1ier.l No reaction pathways for the conversionof (1) to (2) had been proposed, and it seemed to us thatP. E. Hoch and G. B. Stratton, U.S.P. 3,346,596 (Chem. Abs.,1968, 68, 39199a); U.S.P. 3,419,380 (Chem. Abs., 1969, 'SO,67761n); P. E. Hoch, U.S.P. 3,661,998 (Chenz. Abs., 1972, 77,87982h); U.S.P. 3,821,307 (Chem. Abs., 1974, 81, 120111f).M. Perscheid and K. Ballschmiter, 2. ,vatrtrforsch., 1973, H b ,5492582 J.C.S. Perkin Itwo possibilities were those outlined in Schemes 1 and 2.They differ as to whether the initial reaction involves anintramolecular alkoxide ion cyclisation (Scheme 1) orwhether attack of alkoxide ions occurs on the chlorine-substituted double bond prior to intramolecular cyclis-ation (Scheme 2).A convenient procedure for theformation of (2A) is to add, during 1 h, a solution of (1A)in ethanol to a solution of sodium ethoxide in refluxingC I y C I CI -CI1RO-For (51, (6). and ( 7 ) :For (21, (8),and (9):A , n - 1 . R = OE?8; n = 1, R = OMeD i n = 2 , R = OMeA ; n = 1 B ; n = 2C; = 2 , R = OE?4nROHJ I R O -CI "CI( 2 )SCHEME 1ethanol, and then to boil the mixture at reflux for a further2 h. However when the addition is carried out at roomtemperature and stirring is continued for 48 h at roomtemperature, equally good yields of (2A) result. Ifunder these conditions the reaction is worked up after16 h, the i.r.spectrum of the crude product contains aband at 1645 cm-l due to a substituted double bondin addition to that at 1603 cm-l due to the chlorine-substituted double bond in (1A). Both these doublebond absorptions were absent from the i.r. spectrum ofthe product, effectively pure (2A), obtained after 48 h.The cyclic acetal (2A) exhibits an n.m.r. doublet at T 5.43due to CHCl. The n.m.r. spectrum of the crude pro-duct obtained after 16 h, however, showed a more com-plex pattern in the T 5.3-5.5 region, of which the T 5.43doublet was a part, suggesting that, in addition to (2A),another compound containing the structural unit )CHC11For ( 1 ) : A; n = 1 B; n = 2For (21, (91, (10).(111, and (12):A ; n = 1, R = OEt 8; n = 1 , R = OMeC ; n = 2. R = OEt 0; n = 2 , R = OMeSCHEME 2was present. Work-up after 16 h of a large-scale reac-tion at room temperature allowed isolation of the inter-mediates (7A) and (11A). These were recognised fromtheir n.m.r. spectral parameters (see Experimentalsection), and additionally in the case of (7A) by itsidentity with material synthesised by the oxidation of(1A) with lead tetra-acetate or the reaction of (1A) witha suspension of potassium hydroxide in benzene. Theisolation of (7A) and (11A) in the conversion of (1A) into(2A), and the observation that they are not present at theend of the reaction when (2A) is isolated in high yield,strongly support the proposal that they are interme-diates in the formation of (2A) from (1A) via Schemes 1and 2.Intermediate ($A) in Scheme 1 is an anti-Bredtcompound containing a transoid double bond in a seven-membered ring. This does not, however, invalidateScheme 1, since recent work on the enolate of brendan-2-one has demonstrated the existence of such structures.J . Amer. Chem. SOC., 1975, 97, 904.4 A. Nickon, D. F. Covey, Fu-chih Huang, and Yu-Neng ICuo1976 2583The conditions under which compound (1A) reacts withalkoxide ions do not afford any reaction with 1,2,3,4,7,7-he~achloronorborn-2-ene.~ Therefore the 2-endo-hydr-oxymethyl group in (1A) must activate the chlorine-substituted double bond towards reaction with alkoxideions. The hydroxy-group is inductively electron-attract-ing, and if (1A) were to adopt a conformation in whichthe hydroxy-group is directed towards the chlorine-substituted double bond, interaction between the lonepair electrons on oxygen and the x-electrons of the doublebond could lead to an intramolecular OH * x-bondedsystem.5 This would reduce the electron density at thecarbon atoms of the double bond, and make them moresusceptible towards nucleophilic attack.The orientation(13) in which the hydroxy-group is directed towards thechlorine-substituted double bond is supported by then.m.r. spectral data for (1A) and related coinpounds(Table 1). The results suggest that in (IA) the 8-protonsHa and Hb have similar environments. Any alternative(18)For (18) and (19):A ; R = OEt 8 ; R = OMeCI \I CI(20)arrangements, e.g.(14) or (15), would result in one of theC-8 protons being underneath the ring system and hencein a different environment from the other. The couplingconstants J(2-exoJ 8a) and J(2-em, 8b) do not differmarkedly (7.2 and 5.6 Hz) from the values (6.8 Hz) for(16; X = Me). This also supports the conformation(13), since in either (14) or (15) the values for J(2-ex0, Sa)and J(2-ex0, 8b) would differ substantially. This appearsto be the case (see Table 1) in (16; X = C1, Br, or I),which suggests that these molecules prefer conformationsrelated to either (14) or (15) in which the carbon-halogenbond points away from the ring system.1,4,5,6,7,7-HexachIoronorborn-5-en-2-elz~o-ylmethy~methyl ether (17), on the basis of its n.m.r.spectraldata (Table l), may also have an oxygen atom relativelyclose to the chlorine-substituted double bond. As themethoxy-group attracts electrons inductively, it wasexpected that it would activate the chlorine-substituteddouble bond for attack by a nucleophile. This was borneout experimentally when the reactions of (17) with eth-TABLE 1N.m.r. spectral data (90 MHz), for 1,4,5,6,7,7-hexachIoro-norborn-5-en-2-endo-ylmethane derivatives ( 16)CI 7 CI Y P I'i ValuesH-3- H-3- H-2-X endo exo exo Ha-8 Hb-8H 8.37 7.35 7.10 8.95 8.95c1 8.04 7.27 6.79 6.90 6.20Br 8.07 7.27 6.73 7.15 6.39I 8.17 7.28 6.70 7.41 6.53OH 8.11 7.38 6.97 6.58 6.20OMe* 8.26 7.65 7.34 i . 2 1 6.84J l H z3-endo, S-endo, 3-exo, 2-exo, 2-exo, 8a,X 3-exo 2-exo 2-ex0 8a 8b 8bH -11.8 3.5 8.6 6.8 6.8 6.8c1 -12.8 3.7 8.5 1.0 1.5 - 7.7Br -13.0 4.1 8.5 11.3 3.2 -9.7I -13.0 4.3 9.0 11.3 3.3 -9.0OH -12.4 3.9 8.7 7.2 5.6 -10.9OMe -11.3 3.5 8.2 7.8 7.0 -13.0* OCH,, 7.04 (s).oxide and methoxide ions afforded compounds (18A) and(19A), and (18B) and (19B), respectively, identified bytheir spectral data (see Experimental section).In an extension of the conversion of (1A) into (2A) and(2B) the reaction of 1,4,5,6,7,7-hexachloronorborn-5-en-2-elzdo-ylethanol (1B) with ethoxide and methoxide ionswas investigated. The six-membered ring cyclic acetals(2C) and (2D), respectively, were formed under conditionscomparable to those required for the formation of (2A)and (2B) from (1A).Acidic hydrolysis of (2C) and (2D)gave the hemiacetal (3B), often contaminated with thehydroxy-ketone (20). It was possible to isolate (3B) bycrystallisation. Acidic hydrolysis for a prolonged periodgave substantial quantities of (20). The hemiacetal(3B) could be converted into the chIoroketone (4B) bytreatment with phosphorus pentachloride, a reactionanalogous to the formation of (4A) from (3A).A point of interest in the structures of compounds(2C and D) and (3B) is the conformation of the pyranring, which could approach either a boat (22) or achair (21) structure. Information as to the conform-ation is provided by J(l-exo, 2a) and J(1-exo, Zb), whichS. Ueji and T. Kinugasa, Tetrahedyom Letters, 1976, 20372584 J.C.S. Perkin Ishould vary with dihedral angle.In the chair form (21),H-l-exo bisects the angle between the 2-protons Ha andCI CI(21) (22)Hb, and J(l-exo, 2a) and J(l-exo, 2b) should be equal orat least similar. In the boat form (22), H-l-em and H-2aare eclipsed, whereas H-l-exo and H-2b are at the tetra-hedral bond angle, which should result in markedly dif-ferent values for the coupling constants. The observedvalues (Table 2) are in fact Substantially different whichEXPERIMENTALN.m.r. spectral measurements a t 90 MHz were obtainedby using a Bruker HFX 90 instrument.The following compounds were made by literature pro-cedures : 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-y1-methanol ( 1 A),, 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylmethyl chloride ( 16 ; X = C1) , ti 1,4,5,6,7,7-hexachloro-norborn-5-en-2-endo-ylmethyl bromide ( 16 ; X = Br) ,6 and1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylmethyl iodide1,4,~,6,7,7-HexachZoronorbor~-5-en-2-endo-yZmethane ( 16;X = H) .8--Hexachlorocyclopentadiene (22.0 g, 0.08 mol)and propene (5.0 g, 0.12 mol) were heated in a sealed tubeunder nitrogen a t 180 'C for 6 h.The tube was then cooledand opened, and the excess of propene allowed to evaporate.The residue was treated with charcoal and recrystallised frommethanol to afford 1,4,5,6,7,7-hexachZoronorborn-5-en-2-endo-ylmethame (16; X = H) (15.5 g), m.p. 140-141 "C (Found:C, 31.3; H, 2.1. C8H,Cl, requires C, 31.2; H, 1.9%); forn.m.r. data see Table 1; vUL 1 607 cm-l (cis-ClC=CCl).1,4,5,6,7,7-Hexachloronorborn-5-en-2-endo-yZmethylMethyl Ether (17).-Allyl bromide (10 g, 0.082 mol) wasadded dropwise, with stirring, to a solution of iodine (2.2 g,0.096 mol) in dry methanol (74 ml).This solution was(16; x = 11.7TABLE 2N.m.r. spectral data (90 MHz) for 5-exo-alkoxy (or hydroxy)-6-endo,7,8,8,9-pentachloro-4-oxatricyclo[5.2.1 .05* s]decanesCI CIz ValuesCompound R H-l-exo Ha-2 Hb-2 Ha-3 Hb-3 H-6-exo H-lO-endo H-LO-exo(2C) Et * 7.04 7.90 8.44 5.66 6.02 5.24 7.57 7.607.11 7.93 8.41 5.65 6.03 5.25 7.61 7.64 p; 6.99 7.89 8.48 5.51 6.12 5.19 7.49 7.53J I H z1-em, l-exo, 1-exo, 1-exo, 2s. 2a, 2a, 2b, 2b, 3a, 10-endo, 10-exo,Compound R 2a 2b 10-endo 10-exo 2b 3a 3a 3a 3b 3b 10-exo 6-ex0Et 6.0 3.5 8.2 11.0 14.0 3.6 3.5 11.0 5.5 12.5 0 1.5Me 6.6 3.3 8.3 10.8 13.3 3.3 3.3 10.8 5.8 12.3 0 1.7(2C)(2D)(3B) H 4.6 3.3 8.3 11.6 14.1 1.7 3.3 12.8 5.8 12.2 0 2.0* OCH,.CH,, 6.29 (q), 8.78 (t).7 OCH,, 6.58 (s). OH, 6.67 (s).makes the boat conformation (22) or something approach-ing it, much more probable than the chair conformation(21). This may be rationalised by the observation, fromformation (21) is closer to the 6-ertdo-chlorine atom thanis the 3-proton Ha to the 9-chlorine atom in the boat con-ation (22) 9 possibly Of the twist boat type, reducethis latter non-bonded interaction still further.SOC., 1956, 77, 4427; E. K. Fields, ibid., 1954, 76, 2709.41; D. I. Davies and P. Mason, J. Chem. SOC. (C), 1971, 288.boiled a t reflux for 1 h. Careful fractionation affordedally1 methyl ether (5.2 g), b.p.46-47' (lit.,9 45.5-47'). Thisether (5.2 g, 0.072 mol) and hexachlorocyclopentadiene (14.5Fractional distillation afforded the inethyl ether (17) (14.4g), b.p. 92-94' a t 0.3 mmHg; for n.m.r. data see Table 1;vmX. 1 610 cm-1 (cis-ClC=CCl).-Vinylacetic acid (14.0 g, 0.16 mol) dissolved in anhydrousdiethyl ether (30 ml) was added carefully to a suspension ofPrepared by Dr. D. R. Adams, P1i.D. Thesis, London, 1973.J. C. Irvine, J. L. A. MacDonald, and C. Soutar, J. Chem.molecular models, that the 3-proton Hb in the chair con- g, 0.053 mol) were heated in a Carius tube a t 120 'c for 24 h-formation (22)- A distorted version Of the boat 'Onform- 1,4,5,6,7,7-Hexachloyonoybo~n-5-en-2-endo-yzethanoz (1B).6 E T, McBee, H.Rakoff, and R. K. Meyers, J. Amer. Chem.7 R. Riemschneider and H. J. Kolzsch, Monatsh., 1960, 91,Soc., 1915, 107, 3371976 2585lithium aluminium hydride (7.6 g, 0.2 mol) in anhydrousether (80 ml) . The excess of hydride was then destroyed bycareful addition of ethyl acetate and water. The mixturewas then extracted with ether (3 x 100 ml) ; the ether layerwas separated, dried (MgSO,), and evaporated. Distilla-tion of the crude product afforded but-3-en-1-01 (8.4 g), b.p.112-1 14" (lit.,lO 112-1 14"). Hexachlorocyclopentadiene(18 g, 0.066 mol) and but-3-en-1-01 (5 g, 0.069 mol) wereheated in aCarius tube at 160 "C for 24 h. Distillation of thecrude product afforded the alcohol (1B) (21 g), b.p. 124-126"at 0.1 mmHg (Found: C, 31.5; H, 2.45; C1,61.4.C,H8C160requires C, 31.3; H, 2.3; C1, 61.75%); T 7.03 (m, H-2-exo),8.22 (q, H-3-ewdo), 7.34 (q, H-3-exo), 8.76 and 8.07 (CH,=CH,.OH), 6.32 (t, CH,*CH,*OH), and 7.36 (s, OH); vmL1 610 cm-l (cis-ClC=CCl).Reaction of the Alcohol (IA) with Potassium Hydroxide inBenzene.-The alcohol (1A) (5 g, 0.015 mol) was dissolved ina suspension of crushed potassium hydroxide (4.2 g, 0.075mol) in benzene (100 ml), and the mixture boiled a t reflux for17 11. Water (100 ml) was then added, followed by con-centrated hydrochloric acid until pH 7 was reached. Themixture was extracted with ether (3 x 100 ml), and theextract dried (MgSO,) and evaporated; the residue wasdistilled to afford 4-exo, 5-endo, 6,7,7,8-hexachloro-3-oxa-tricyc1o[4.2.1.O4~~]nonane (7) (2 g), b.p.89-gloat 0.01 mmHg(Found: C , 28.75; H, 1.8. C8H,&O requires C, 29.0; H,1.8%) ; T 7.31 (m, H-l-exo), 5.35 (d, H-5-exo), 7.43 (9, H-9-endo), 7.37 (oct, H-9-exo), and 6.10 (9) and 5.67 (9) (CH,*O);no double-bond i.r. absorption; M f 332.Oxidation of the Alcohol (1A) .-Anhydrous benzene (18ml), the alcohol (1A) (6 g, 0.015 mol), lead tetra-acetate(7.1 g, 0.016 mol), and calcium carbonate (1.66 g, 0.016 5mol) were placed in a 100 ml flask equipped with a waterseparator containing potassium carbonate. The mixturewas stirred and heated at reflux for 8 h, then washed withwater, dried, and filtered, and evaporated. The residuewas distilled to afford 4-exo,5-endo, 6,7,7,8-hexachloro-3-oxatric~clo[4.2.1.04~8]nonane (7) (0.21 g ) with properties asabove, followed by 1,2,3,4,7,7-hexachloronorborn-2-en-5-endo-ylmethyl acetate (5.05 g), b.p. 116-118" a t 0.01 mmHg(lit.,6 154-155" at 2 mmHg).Isolation of Intermediates in the Reaction of the Alcohol (1A)with Sodiuiw Ethoxide.-The alcohol (1A) (1 g, 0.003 mol)dissolved in absolute ethanol (2.5 ml) was added to a solutionof sodium ethoxide [sodium (0.3 g , 0.013 g atom) in ethanol(12 ml)]. The mixture was stirred a t room temperatureovernight (16 h), water (12 ml) was then added, and thepH was adjusted to 7 with concentrated hydrochloric acid.The precipitated solid cyclic acetal (2A), m.p.114-1 15"(lit.,l 110-111.5") was filtered off, and the filtrate extractedwith chloroform (3 x 25 ml). The extract was dried (Mg-SO,), filtered, and evaporated.The residue was separatedinto three components by preparative plate chromatography(20 cm x 20 cm; Kieselgel GF254) with a 4 : 1 benzene-lightpetroleum (b.p. 40-60 "C) as eluant: (i) the cyclic acetal(ZA), m.p. 112" (lit.,1 110-111.5°); (ii) 1,4,5,7,7-Penta-chloro-6-ethoxynorborn-5-en-2-endo-yl~nethanol (1 1A) (0.1 g),b.p. 80-83O at 0.1 mmHg (Found: C, 35.45; H, 3.3.Cl,HllCl,O, requires C, 35.25; H, 3.25%); T 7.0 (m, H-2-exo), 8.12 (9, H-3-endo), 7.35 (q) H-3-exo),6.72 (q) and 6.22(q) (CH,.OH), 8.16 (s, OH), 5.62 (9, O*CH,*CH,), and 8.61(t, OCH,.CH,); v,, 3 340 and 3 620 (OH) and 1 645 cm-1(cis-EtO.C=CCl) ; M+ 340; (iii) 4-exo,5-endo,6,7,7,8-hexa-chloro-3-oxatricyclo[4.2.1.04~8]nonane (7) (0.1 g) ; propertiesas recorded earlier.When the reaction was carried out for48 h instead of 16 h, only the cyclic acetal (2A) 95% wasobtained.Reaction of the Alcohol (1B) with Sodium Ethoxide.-Asolution of the alcohol (1B) ( 5 g, 0.014 5 mol) in ethanol (11ml) was added over 0.4 h to a solution of sodium ethoxide[sodium (1.334 g, 0.058 g atom) in ethanol (57 ml)] a t ca.74 "C. The mixture was then boiled a t reflux for a further2 h. Water (58 ml) was then added, followed by concen-trated hydrochloric acid until pH 7 was reached. The mix-ture was extracted with chloroform (3 x 100 ml) and theextract dried (MgSO,) and evaporated. The residue wasdistilled to afford 6-endo, 7,8,8,9-~entachloro-li-exo-ethoxy-4-oxatricyclo[5.2.1.0~~9]decane (2C) (4.6 g), b.p.103-104"a t 0.02 mmHg, m.p. 64-65' (from n-pentane) (Found: C,37.45; H, 3.75. CllH1,Cl,O, requires C, 37.25; H, 3.65%);for n.m.r. data see Table 2; no double-bond i.r. absorption.Reaction of the Alcohol (1B) with Sodium 1Methoxide.-Thealcohol (1B) (5 g, 0.0145 mol) was dissolved in methanol(1 1 ml) and added dropwise over 0.5 h to a solution of sodiummethoxide [sodium (1.334 g, 0.058 g atom) in methanol(57 ml)] a t ca. 65 "C. The mixture was then boiled a t refluxfor a further 17 h. Water (58 ml) was then added, followedby concentrated hydrochloric acid until pH 7 was reached.The mixture was then extracted with chloroform (3 x 100ml) and the extract dried (MgSO,) and evaporated. Theresidue was distilled to afford 6-endo, 7,8,8,9-pentachloro-5-exo-methoxy-4-oxatricyclo[5.2. l.OS*g]decane (2D) (4.4 g), b.p.106-107" a t 0.04 mmHg, m.p.99-100' (from methanol)(Found: C, 35.25; H, 3.15. Cl,Hl,C150, requires C , 35.25;H, 3.25%) ; for n.m.r. data see Table 2.Reaction of the Acetal (2D) with Concentrated SulphuricAcid-The acetal (2D) (6 g, 0.017 mol) mixed with con-centrated sulphuric acid (18.39 g ) was stirred and warmedat 70 "C for 1 h. The mixture was then added to water (141 g)and the suspension warmed to ca. 70 "C and allowed to cool.The mixture was extracted with ether (3 x 100 ml) and theextract dried (Na,SO,) and evaporated. The residue wasdistilled to afford 6-endo, 7,8,8,9-pentachloro-4-oxatricycko-[5.2.1.05~9]decan-5-exo-ol (3B) (4 g), b.p. 112-114" a t 0.01mmHg, m.p.93-94" (from carbon tetrachloride) (Found :C, 33.05; H, 2.65. C,H,C1502 requires C, 33.1 ; H, 2.75%) ;for n.m.r. data see Table 2; vmx. 3 570 cm-1 (OH) (crudesample showed C=O bond a t 1795 cm-l, absent fromspectrum of recrystallised product).The hemiacetal (3B) (7 1 yo) could be prepared by a similarprocedure from (2C).Conversion of the Hemiacetak (3B) into the Chloro-ketone(PB).-The hemiacetal(3B) (1 g, 0.003 mol) mixed with phos-phorus pentachloride (0.8 g, 0.003 6 mol) was stirred andwarmed gently. When the temperature reached 55-60 "Can exothermic reaction occurred and hydrogen chloride wasevolved. The solution was maintained a t a gentle refluxfor 3 h and then poured onto crushed ice. The resultantmixture was extracted with n-hexane and the extract dried(Na,SO,) and evaporated.The residue was crystallisedfrom n-pentane to afford 1,3-endo,4,7,7-~erttachloro-6-endo-(2-chloroethyl)norbornan-2-one (4B) (0.75 g), m.p. 85-86"(Found: C , 31.55; H, 2.25. C,H8C160 requires C, 31.3;H, 2.3%); 7 7.14 (m, H-6-exo), 7.34 (9, H-Ei-endo), 7.26 (9,H-5-exo), 5.08 (d, H-3-exo), 8.41 (m) and 8.00 (m) (CH,*CH,-Cl), and 6.43 (q, CH,*CH,Cl), vmX. 1 795 cm-1 ()GO).Conversion of the Acetal(2C) into the Hydroxy-ketone (20).-The acetal(2C) 2 g, 0.005 6 mol) was mixed with concentratedlo E. Grischkevitsch-Trochimovski, J . Russ. Phys. Chem. SOL,1916, 48, 880J.C.S. Perkin Isulphuric acid (6.2 g) , warmed to ca. 80 "C, and kept at thistemperature for 5 h with stirring.The mixture was thenadded to water (50 ml) and the resulting suspension warmedto ca. 70 "C and allowed to cool. The mixture was extractedwith ether ( 3 x 50 ml), and the extract dried (Na,SO,) andevaporated. Distillation afforded 1,3-endo,4,7,7-fienta-chloro-6-endo- (2-hydroxyethyl)norbornan-2-one (20) (0.55 g) ,b.p. 123-126" at 0.2 mmHg (Found: C, 32.8; H, 2.8.C,H,C1,0, requires C, 33.1, H, 2.75%); T (60 MHz) 6.92(m, H-6-exo), 7.33 (q, H-5-endo), 7.24 (q, H-5-exo), 5.09(d, H-3-exo), 8.04 (m) and 8.53 (m) (CH,CH,*OH), 6.74 (t,CH,-CH,-OH), and 7.20 (s, OH) ; vmaX 3 560 (OH) and 1 796cm-1 (=GO).Reaction of 1,4,5,6,7,7-Hexachloronorborn-5-en-2-endo-ylmethyl Methyl Ether (17) with Sodium Ethoxide.-Method A.The methyl ether (17) (2 g, 0.005 8 mol) dissolved in ethanol( 5 ml) was added to a solution of sodium ethoxide [sodium(0.56 g, 0.024 g atom) in ethanol (24 ml)] and the mixturestirred for 17 h at room temperature. Water (25 ml) wasthen added followed by dilute hydrochloric acid until pH 7was reached.The suspension was extracted with ether( 3 x 30 ml) and the extract dried (MgSO,) and evaporated.The residue was separated by preparative plate chromato-graphy (20 x 20 cm; Kieselgel GF254) with light petroleum(b.p. 40-60 "C) as eluant to afford the unchanged methylether (17) and 1,4,5,7,7-~entachloro-6-ethoxynorborn-5-en-2-endo-ylmethyl methyl ether (18A) (0.35 g ) , b.p. 99-101" at0.45 mmHg (Found: C, 37.4; H, 3.7. CllH,,Cl,O, re-quires C, 37.25; H , 3.65%), T 7.20 (m, H-2-exo), 8.08 (q, H-3-endo), 7.46 (q, H-3-exo), 6.98 (q) and 6.52 (q) (CH,*O*CH,), 6.73 (s, OCH,), 6.42 (q, O*CH,-CH,), and 8.78 (t,O-CH,*CH,) ; vms.1 640 cm-1 (cis-EtO*C=CCl).The methyl ether (17) (2 g, 0.005 8 mol) wasdissolved in ethanol ( 5 ml) and added to a solution ofsodium ethoxide [sodium (0.56 g, 0.024 g atom) in ethanol(25 ml)]; the mixture was stirred at room temperature for60 h. Water (25 ml) was then added, followed by concen-Method B.trated hydrochloric acid until pH 7 was reached. Themixture was extracted with ether ( 3 x 50 ml) and the ex-tract dried (MgSO,) and evaporated. The residue wasseparated by preparative plate chromatography (20 x 60cm ; Kieselgel GF,,,) with light petroleum (b .p. 40-60 "C) aseluant to afford unchanged (17), (18A) (0.2 g), and 1,4,7,7-tetrachloro- 5,6-diethoxynorborn-5-en-2-endo-yZmethyl methylether (19A) (0.12 g ) , b.p. 106-108" at 0.4 mmHg (Found: C,42.55; H, 4.85. Cl3H1,Cl,O, requires C, 42.86; H, 4.95%) ;-G 7.16 (m, H-2-exo), 8.03 (9, H-&endo), 7.41 (q, H-3-exo),6.95 (9) and 6.47 (q) (CH,-OCH,), 6.71 (s OCH,), 6.41 ( 4H, q, O.CH,*CH,), and 8.77 (6 H, t, O.CH,*CH,); vmax. 1 618cm-1 (cis-EtO-C=C*OEt).Reacti0.l.t of 1,4,5,6,7,7-HexachZoronorborn-5-en-2-endo-ylmethyl Methyl Ether ( 1 7 ) with Sodium Methoxide.-Bymethod B (above) the reaction between the methyl ether(17) ( 2 g, 0.005 8 mol) and sodium methoxide [from sodium(0.56 g) in methanol (25 ml)] afforded 1,4,5,7,7-fientachloro-6-nzethoxynorborn-5-en-2-endo-yZmethyl methyl ether ( 18B) (0.34g) b.p. 60-62" at 0.06 mmHg (Found: C, 35.5; H, 3.3.C1,Hl1C1,O2 requires C, 35.25; H, 3.25%) ; T 7.15 (ni, H-2-exo), 8.08 (q, H-3-endo), 7.48 (9, H-3-exo), 6.96 (4) and6.52 (q) (CH,*O*CH,), 6.74 ( s , CH2*0.CH,), and 6.65 (s,OCH,) ; v-. 1 650 cm-l (cis-MeO*C=CCl) ; and 1,4,7,7-tetrachloro-5,6-dimethoxynorborn-5-en-2-endo-yZmethyZmethyl ether (19B) (0.28 g), b.p. 67-69" at 0.06 mmHg(Found: C, 39.05; H, 4.15. C,lH14Cl,0, requires C, 39.3;H, 4.15%); T 7.12 (m, H-2-exo), 8.05 (q, H-3-endo), 7.46 (9,H-3-exo), 6.93 (q) and 6.49 (q) (CH,-O*CH,), 6.73 (s, CH,*0-CH,), 6.66 ( 3 H, s, OCH,), and 6.63 ( 3 H, s, OCH,); vmaX-1 620 cm-1 (cis-MeO*C=C-OMe).We thank Dr. J. M. Briggs for help with the spectralmeasurements, and the KCL (1916) Research Fund forfinancial support (to A. L. B. G.).[6/1336 Received, 12th July, 1976
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