Asymmetric synthesis of chloroisothreonine derivatives via syn-stereoselective Mannich-type additions across N-sulfinyl-α-chloroimines
作者:Gert Callebaut、Filip Colpaert、Melinda Nonn、Loránd Kiss、Reijo Sillanpää、Karl W. Törnroos、Ferenc Fülöp、Norbert De Kimpe、Sven Mangelinckx
DOI:10.1039/c4ob00243a
日期:——
Mannich-type reactions of O-Boc glycolic esters across chiral N-sulfinyl-α-chloroaldimines resulted in the efficient and syn-stereoselective synthesis of new γ-chloro-α-hydroxy-β-amino esters (dr > 99 : 1). The α-coordinating ability of the chlorine atom was of great importance for the diastereoselectivity of the Mannich-type reaction and overruled the chelation of the sulfinyl oxygen with the lithium