Synthesis of α-Phosphorylated α,β-Unsaturated Imines and Their Selective Reduction to Vinylogous and Saturated α-Aminophosphonates
摘要:
[GRAPHIC]An efficient synthesis of alpha,beta-unsaturated imines derived from alpha-aminophosphonates is achieved through aza-Wittig reaction of P-trimethyl phosphazenes with beta,gamma-unsaturated alpha-ketophosphonates. Selective 1,2-reduction of such 1-azadienes affords beta,gamma-unsaturated alpha-aminophosphonates, phosphorylated analogs of vinylglycines, which are hydrogenated to yield saturated alpha-aminophosphonate derivatives.
Catalytic Enantioselective Hetero Diels−Alder Reactions of α,β-Unsaturated Acyl Phosphonates with Enol Ethers
作者:David A. Evans、Jeffrey S. Johnson
DOI:10.1021/ja980423p
日期:1998.5.1
reactions with high enantioselectivities. In these processes, the unifying organizational motif is that the substrate undergoing activation is capable of chelating to the chiral cationic Cu(II) catalyst, a condition that frequently affords high enantioselection. 4 The purpose of this paper is to present our findings thatR,â-unsaturated acyl phosphonates undergo enantioselective hetero Diels -Alder
Enantioselective Synthesis of Dihydropyrans. Catalysis of Hetero Diels−Alder Reactions by Bis(oxazoline) Copper(II) Complexes
作者:David A. Evans、Jeffrey S. Johnson、Edward J. Olhava
DOI:10.1021/ja992175i
日期:2000.3.1
C2-symmetric bis(oxazoline)−Cu(II) complexes 1 and 2 catalyze the inverse electron demand hetero Diels−Alder reaction of α,β-unsaturated carbonyl compounds (heterodiene) with electron-rich olefins (heterodienophile) in high diastereo- and enantioselectivity. α,β-Unsaturated acyl phosphonates and β,γ-unsaturated α-keto esters and amides are effective heterodienes, while enol ethers and sulfides function
[GRAPHIC]An efficient synthesis of alpha,beta-unsaturated imines derived from alpha-aminophosphonates is achieved through aza-Wittig reaction of P-trimethyl phosphazenes with beta,gamma-unsaturated alpha-ketophosphonates. Selective 1,2-reduction of such 1-azadienes affords beta,gamma-unsaturated alpha-aminophosphonates, phosphorylated analogs of vinylglycines, which are hydrogenated to yield saturated alpha-aminophosphonate derivatives.