以天然L-脯氨酸为原料,经酯化、氨基保护、格氏反应和催化氢解等4步反应合成了光学活性的β-氨基醇.将其作为催化剂用于二烷基锌和醛的不对称加成反应,分别考察了催化剂结构、用量、溶剂、反应温度等因素.结果表明,当催化剂质量分数为5%,甲苯作溶剂,在-10℃下,以(S)-N-苄基-2-吡咯烷-α,α-二(α-萘基)甲醇(3)作催化剂时,所得仲醇的对映体过量(e.e.)最高为82%,产率高达到100%.
Chiral β-amino alcohols, using L-proline as raw material, were synthesized by esterization, protection of amino-group, Grignard reaction and catalytic hydrogenolysis. They were used as chiral catalysts in the asymmetric addition of diethylzinc to aldehydes. The effects of the amount structure of and the catalysts, solvent and reaction temperature on enantioselectivity were also studied. When the molar fraction of catalyst 5 % was relative to aldehyde was used, wth toluene as solvent at -10 ℃, (S)-N-benzyl-2-( di-α-naphthylhydroxymethyl) pyrrolidine (3) was successfully applied to the catalytic enantioselective addition of diethylzinc to aldehydes to give sec-alcohols in a good to high yields up to 82% enantiomeric excesses.