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

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

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%.

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.