(4S)-苯氧基-(S)-脯氨酸催化直接不对称羟醛缩合反应

Direct Asymmetric Aldol Reactions Catalyzed by (4S)-Phenoxy-(S)-proline

N 乙氧羰基 ( 4R) 羟基 (S) 脯氨酸甲酯与苯酚的Mitsunobu反应给出N 乙氧羰基 ( 4S) 苯氧基 (S) 脯氨酸甲酯 ,后者经皂化和盐酸水解后得标题氨基酸 .这一化合物 ( 5mol% )对映选择性催化丙酮和取代苯甲醛的羟醛缩合反应 ,产率67.4%～ 89.9% ,ee最高达 76.5 % .

The Mitsunobu reaction of N-ethoxycarbonyl-(4R)-hydroxy-(S)-proline methyl ester with phenol afforded (4S)-phenoxy-(S)-proline methyl. ester, which, after saponification and hydrolysis in hydrochloric acid, gave the title amino acid. This compound (5 mol%) catalyzes aldol reaction of acetone with benzaldehydes enantioselectively in the yields ranging from 67.4% to 89.9%, with the ee up to 76.5%.