Optically pure 1,3,2-oxazasilolidine derivatives were synthesized from a chiral 1,2-amino alcohol. These heterocyclic compounds containing a stereogenic silicon atom produced tertiary silanes with excellent optical purity through successive reactions with Grignard reagents and diisobutylaluminum hydride. Stereochemical course of the reactions of the oxazasilolidine at the chiral silicon atom was elucidated based on the absolute configurations of the products and the substrate which were determined by chiral HPLC and X-ray crystallographic analyses. (C) 2009 Elsevier B. V. All rights reserved.
Catalytic Diastereo‐ and Enantioconvergent Synthesis of Vicinal Diamines from Diols through Borrowing Hydrogen
We present herein an unprecedented diastereoconvergent synthesis of vicinal diamines from diols through an economical, redox-neutral process. Under cooperative ruthenium and Lewis acid catalysis, readily available anilines and 1,2-diols (as a mixture of diastereomers) couple to forge two C−N bonds in an efficient and diastereoselective fashion. By identifying an effective chiral iridium/phosphoric
A stoichiometric reagent-free deracemization strategy based on photoredox-neutral catalysis is developed. The strategy offers precise access to biologically important α-amino esters and variants with high yields and ee values. The efficiency of deracemization is determined by enantiocontrol of the protonation as the stereocentre-forming step. The method is also viable for the synthesis of enantioenriched