Noncovalent Organocatalytic Synthesis of Enantioenriched Terminal Aziridines with a Quaternary Stereogenic Center
作者:Claudia De Fusco、Tiziana Fuoco、Gianluca Croce、Alessandra Lattanzi
DOI:10.1021/ol3017066
日期:2012.8.17
A high-yielding and enantioselective access to novel N-Boc terminal aziridines, bearing a quaternarystereogeniccenter, has been developed via an aza-Michael initiated ring-closure (aza-MIRC) reaction of α-acyl acrylates with an N-tosyloxy tert-butyl carbamate catalyzed by a chiral amino thiourea. The feasibility of the aziridine regioselective ring-opening to valuable α,α-disubstituted α-amino acid
The first one‐pot tandem Michael addition/enantioselective Conia‐ene cyclization of N‐protected prop‐2‐yn‐1‐amines with 2‐methylene‐3‐oxoalkanoates promoted by chiral iron(III)/silver(I) cooperative catalysts has been developed. Alkyl 4‐methylenepyrrolidine‐3‐acyl‐3‐carboxylates, which can be transformed into β‐proline derivatives, are obtained in high yield with high enantioselectivity.
from racemic allenes, and high levels of enantioselectivity are generally obtained for the tetrahydropyridine products with an E-exo-double bond in a (4 + 2) annulation pattern. Moreover, switchable regiodivergent (4 + 1) or (4 + 2) annulations with different types of racemic allenes can be accomplished via ligand control. In addition, similar oxapalladacycles of Pd(0) and activated enones can be generated