Synthesis of Arylglycine and Mandelic Acid Derivatives through Carboxylations of α-Amido and α-Acetoxy Stannanes with Carbon Dioxide
摘要:
Incorporation reactions of carbon dioxide (CO2) with N-Boc-alpha\-amido and a-acetoxy stannanes were developed using CsF as a mild tin activator. Monoprotected alpha-amido stannanes could be used, and the corresponding arylglycine derivatives were obtained in moderate-to-high yields under 1 MPa (10 atm) of CO2 pressure. alpha-Acetoxy stannanes also underwent carboxylation to afford mandelic acid derivatives in excellent yields under ambient CO2 pressure. Both transformations enabled the synthesis of alpha-tertiary and alpha-quaternary carboxylic acid derivatives. In addition, the chirality of (S)-N-tert-butylsulfonyl-alpha-amido stannanes was transferred with up to 90% inversion of configuration at 100 degrees C.
Applications of α-alkoxyorganocuprate reagents in the regiospecific synthesis of cyclic homoaldol products
作者:Russell J. Linderman、Alex Godfrey、Kelly Horne
DOI:10.1016/0040-4020(89)80077-8
日期:1989.1
Cyclic homoaldol products have been prepared viaconjugateaddition of α-alkoxyorganocuprate reagents to enones. The reactions are regiospecific, providing the homoaldol products in good to excellent yields. The preparation of the cuprates from the α-alkoxyorganostannane precursor is described in detail. Best results were obtained with the higher order cyano cuprate reagent using in-situ trimethylsilyl