手性Salen及Ga(Salen)催化苯基锂对环氧环己烷对映选择性开环反应

合成了14个含1,2-环己二胺、1,2-二苯基乙二胺或邻苯二胺的手性Salen化合物, 研究了手性Salen直接催化苯基锂对环氧环己烷的不对称开环反应, 结果表明二胺的结构和苯环上3,3'-位取代基对反应的对映选择性有很大的影响. 用Salen与 Me₃Ga原位生成的Ga(Salen)催化苯基锂对环氧环己烷的不对称开环反应, 与用Salen直接催化相比, 得到了更好的化学产率和对映选择性. 当用Ga(Slane) 15为催化剂时, 最佳ee值为73%.

Enantioselective Ring-Opening Reaction of Cyclohexene Oxide with Phenyl Lithium Catalyzed by Salen and Ga(Salen)

Fourteen Salen ligands derived from 1,2-cyclohexanediamine, 1,2-diphenylethylenediamine or 1,2-phenylenediamine were synthesized and also used as catalysts to the enantioselective ring-opening reaction of cyclohexene oxide with phenyl lithium. Results indicated that enantioselectivity was greatly influenced by the structure of the chiral diamine moiety and substituents at 3,3'-positions in benzene ring. The enantioselective ring-opening reaction of cyclohexene oxide with phenyl lithium was also investigated via catalysis by some Ga(Salen) compounds derived from Salen and Me₃Ga, and better yields and enantioselectivities were afforded than those of reaction directly catalyzed by Salen. Enantioenriched trans-phenylcyclo-hexanol was obtained in up to 73% ee when Ga(Salen) 15 was used as the catalyst.