Enantioselective Addition of Vinylzinc Reagents to Aldehydes Catalyzed by Modular Ligands Derived from Amino Acids
作者:Meaghan L. Richmond、Christopher M. Sprout、Christopher T. Seto
DOI:10.1021/jo051313l
日期:2005.10.1
enantioselectivities that ranged from 52 to 91% ee and yields that ranged from 40 to 90%. This ligand was especially effective for the reaction of aromatic aldehydes with vinylzinc reagents derived from bulky terminal alkynes. Ligand 3d catalyzed the addition of (E)-(3,3-dimethylbut-1-enyl)(ethyl)zinc to 2-naphthaldehyde to give (R,E)-4,4-dimethyl-1-(naphthalene-1-yl)pent-2-en-1-ol in 89% ee. The ee of this
由Boc保护的氨基酸合成了一系列基于N-酰基乙二胺的配体。筛选配体催化乙烯基锌试剂向醛的不对称加成的能力。使用位置扫描方法针对该反应优化了配体上的三个多样性位点。发现优化的配体3d可以催化15种不同的(E)-烯丙基醇的形成,其对映选择性为52-91%ee,产率为40-90%。该配体对于芳族醛与衍生自庞大末端炔烃的乙烯基锌试剂的反应特别有效。配体3d催化了(E)-(3,3-二甲基丁-1-烯基)(乙基)锌合成2-萘醛,得到(R,E)-4,4-二甲基-1-(萘-1-基)戊-2-烯- 1-ol在89%ee中。通过单次重结晶,该产品的ee可以提高到97%。