Rh(II)-Catalyzed Reactions of Diazoesters with Organozinc Reagents

详细信息    查看全文

• 作者：Robert Panish ; Ramajeyam Selvaraj ; Joseph M. Fox
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：August 21, 2015
• 年：2015
• 卷：17
• 期：16
• 页码：3978-3981
• 全文大小：345K
• ISSN：1523-7052

文摘

Rh(II)-catalyzed reactions of diazoesters with organozinc reagents are described. Diorganozinc reagents participate in reactions with diazo compounds by two distinct, catalyst-dependent mechanisms. With bulky diisopropylethyl acetate ligands, the reaction mechanism is proposed to involve initial formation of a Rh-carbene and subsequent carbozincation to give a zinc enolate. With Rh₂(OAc)₄, it is proposed that initial formation of an azine precedes 1,2-addition by an organozinc reagent. This straightforward route to the hydrazone products provides a useful method for preparing chiral quaternary 伪-aminoesters or pyrazoles via the Paul鈥揔norr condensation with 1,3-diketones. Crossover and deuterium labeling experiments provide evidence for the mechanisms proposed.