1552271-23-4Relevant articles and documents
A Catalyst Designed for the Enantioselective Construction of Methyl- and Alkyl-Substituted Tertiary Stereocenters
Claraz, Aurlie,Sahoo, Gokarneswar,Berta, Dnes,Madarsz, dm,Ppai, Imre,Pihko, Petri M.
, p. 669 - 673 (2016/02/27)
Tertiary methyl-substituted stereocenters are present in numerous biologically active natural products. Reported herein is a catalytic enantioselective method for accessing these chiral building blocks using the Mukaiyama-Michael reaction between silyl ketene thioacetals and acrolein. To enable remote enantioface control on the nucleophile, a new iminium catalyst, optimized by three-parameter tuning and by identifying substituent effects on enantioselectivity, was designed. The catalytic process allows rapid access to chiral thioesters, amides, aldehydes, and ketones bearing an α-methyl stereocenter with excellent enantioselectivities, and allowed rapid access to the C4-C13 segment of (-)-bistramide A. DFT calculations rationalized the observed sense and level of enantioselectivity.
Development of ProPhenol ligands for the diastereo- and enantioselective synthesis of β-hydroxy-α-amino esters
Trost, Barry M.,Miege, Frederic
supporting information, p. 3016 - 3019 (2014/03/21)
A zinc-ProPhenol-catalyzed direct asymmetric aldol reaction between glycine Schiff bases and aldehydes is reported. The design and synthesis of new ProPhenol ligands bearing 2,5-trans-disubstituted pyrrolidines was essential for the success of this process. The transformation operates at room temperature and affords syn β-hydroxy-α-amino esters in high yields with good to excellent levels of diastereo- and enantioselectivity.