Noritake Shun, Shibata Norio, Nomura Yoshinori, Huang Yiyong, Matsnev Andrej, Nakamura Shuichi, Toru Takeshi, Cahard Dominique
Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan.
Org Biomol Chem. 2009 Sep 7;7(17):3599-604. doi: 10.1039/b909641h. Epub 2009 Jul 10.
Chiral nonracemic guanidines act as Brønsted bases to generate guanidinium enolates for the enantioselective electrophilic trifluoromethylation of beta-keto esters by means of S-(trifluoromethyl)dibenzothiophenium tetrafluoroborate (Umemoto reagent) with good enantioselectivity of 60-70% range. Despite the fact that the ees are still improvable, the model reported in this work could spark the imagination of chemists to design new chiral bases to improve the stereochemical outcome.
手性非外消旋胍作为布朗斯特碱，通过S-(三氟甲基)二苯并噻吩四氟硼酸盐（梅本试剂），生成胍基烯醇盐，用于β-酮酯的对映选择性亲电三氟甲基化反应，对映选择性良好，在60%-70%范围内。尽管对映体过量值仍有提高空间，但本工作报道的模型可能会激发化学家设计新的手性碱以改善立体化学结果的想象力。
