Enantioselective Reduction of Racemic Three-Membered Heterocyclic Compounds. 3. Reaction of Epoxides with B-Isopinocampheyl-9-borabicycolo[3.3.1]nonane-Potassium Hydride and Potassium B-Isopinocampheyl-9 boratabicyclo[3.3.1]nonane Systems1

摘要

Reaction of Rh(Cl04)(CO)(PPh3)2 (1) with trans-C6H5CH = CHCH2OH (2) produces a new cationic rhodium(Ⅰ) complex, [Rh(trans-C6H5CH = CHCHO)(CO)(PPh3)2]ClO4 (3) where 2 is coordinated through the oxygen atom but not through the olefinic group. At room temperature under nitrogen, complex 1 catalyzes dehydrogenation, hydrogenolysis, and isomerization of 2 to give trans-C6H5CH = CHCHO (4), trans-C6H5CH = CHCH3 (5) and C6H5CH2CH2CHO (6), respectively, and oligomerization of 2 whereas under hydrogen, complex 1 catalyzes hydrogenation of 2 to give C6H5CH2CH2CH2OH (7) and hydrogenolysis of 2 to 5 which is further hydrogenated to C6H5CH2CH2CH3 (8). The dehydrogenation and hydrogenolysis of 2 with 1 suggest an interaction between the rhodium and the oxygen atom of 2, whereas the isomerization and hydrogenation of 2 with 1 indicate an interaction between the rhodium and the olefinic system of 2