Synthesis of Chiral<i>N</i>-Sulfonyl and<i>N</i>-Phosphinoyl α-Halo Aldimine Precursors
作者:Gretchen R. Stanton、Mehmet Göllü、Rebecca M. Platoff、Corinne E. Rich、Patrick J. Carroll、Patrick J. Walsh
DOI:10.1002/adsc.201200864
日期:2013.3.11
aldimines have emerged as an important class of synthetic intermediates. The stability and reactivity of α‐halo aldimines can vary greatly depending on the nitrogen protecting group. A general synthesis of stable, chiral α‐halo‐N‐sulfonyl and N‐phosphinoyl aldimine precursors is presented (42–96% yield). The corresponding α‐halo aldimines can be isolated upon treatment with a mild base. Enantioenriched α‐chloro
Reduction of α-fluoro α,β-unsaturatedaldehydes, esters and ketones to the corresponding saturated compounds is readily achieved by catalytic hydrogenation on Pd/C. The same reduction with α,β-difluoro α,β- unsaturated ketones gives various results depending on the solvent.