Synthesis and reactivity of neutral vinylidene and #sigma#-alkynyl complexes containing the hemilabile ligand Ph_2PCH_2CH_2OMe Part 16. Ruthenium tris(pyrazolyl)borate complexes

摘要

RuTp(COD)Cl reacts readily with Ph_2PCH_2CHOMe to give the neutral complex RuTp(k~1(P)-Ph_2PCH_2CH_2OMe)CI (2) which transforms with terminal alkynes HC-=CR (R = Ph, n-Bu, C_6H_9) and carbon monoxide, respectively, into the neutral vinylidene complexes RuTP("'(P)-Ph_2PCH_2CH_2OMe)(CI)(=C=CHR) (3a-c) and RuTp(,,'(P)-Ph_2PCH_2CH_2OMe)(CI)(CO) (4). The "I(P) bonding mode of the phosphinoether testifies to its hemilabile nature. Complex 3a reacts with lithium diisopropylamide to give the neutral cx-acetylide complex RuTp(P,O)-Ph_2PCH_2CH_2OMe)(-C=CPh) (5) which couples with stoichiometric amounts of HC=CPh to give RuTp("I(P).Ph_2PCH_2CH_2OMe)(C(Ph)=CHC=CPh) (6), featuring a 0',1l2-bound enynyl ligand. Treatment of Ja with AgCF_3S0J affords the cationic vinylidene complex [RuTp(,2(P.O)-Ph_2PCH_2CH_2OMe)(=C=CHPh)]CF:1S0J (7). Complex 5 is found to catalyze the dimerization of HC=CR (R=Ph, SiMe_3. n-Bu, t-Bu, C_6H_9) to give enynes. The structures of 3a,4,5 and 7 have beendetennined by X-ray crySta1Iography.