Rapid Access to α-Alkoxy and α-Amino Acid Derivatives through Safe Continuous-Flow Generation of Diazoesters
作者:Hannah E. Bartrum、David C. Blakemore、Christopher J. Moody、Christopher J. Hayes
DOI:10.1002/chem.201101590
日期:2011.8.22
highly efficient continuous‐flow process has been developed for the synthesis of diazoesters from arylsulfonylhydrazones by means of in‐flow Bamford–Stevens reactions. Furthermore, a range of α‐alkoxy and α‐amino acid derivatives have been prepared in excellent yields through rhodium(II)‐mediated OH and NHinsertions, without the need to isolate or handle the potentially hazardous diazo species (see
Chemo- and Enantioselective Pd/B Hybrid Catalysis for the Construction of Acyclic Quaternary Carbons: Migratory Allylation of <i>O</i>-Allyl Esters to α-<i>C</i>-Allyl Carboxylic Acids
We describe herein the asymmetric synthesis of α-allyl carboxylic acids containing an α-quaternarystereocenter by a chiral hybrid catalyst system comprising palladium and boron complexes. The reaction proceeded through palladium-catalyzed ionization of α,α-disubstituted O-allyl esters for the generation of chiral π-allyl palladium complex as an electrophile, boron-catalyzed enolization of the carboxylate