Bifunctional Iminophosphorane Organocatalysts for Enantioselective Synthesis: Application to the Ketimine Nitro-Mannich Reaction
作者:Marta G. Núñez、Alistair J. M. Farley、Darren J. Dixon
DOI:10.1021/ja409121s
日期:2013.11.6
readily synthesized via a last step Staudinger reaction of a chiral organoazide and a triarylphosphine. Their application to the first general enantioselective organocatalytic nitro-Mannichreaction of nitromethane to unactivated ketone-derived imines allows the enantioselective construction of β-nitroamines possessing a fully substituted carbon atom. The reaction is amenable to multigram scale-up, and the
The present invention provides a bifunctional catalyst of the formula (1): wherein: each R
1
is independently selected from an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aryl group, an optionally substituted heteroaryl group, an optionally substituted aralkyl group and an optionally substituted alkaryl group; Z represents a divalent organic linking moiety optionally containing one or more stereocentres; and EWG represents an electron-withdrawing group.
(R
1
)
3
P═N—Z—NH-EWG (1)
Catalytic Enantioselective Intramolecular Oxa-Michael Reaction to α,β-Unsaturated Esters and Amides
作者:Guanglong Su、Michele Formica、Ken Yamazaki、Trevor A. Hamlin、Darren J. Dixon
DOI:10.1021/jacs.3c03182
日期:2023.6.14
bifunctional iminophosphorane (BIMP)-catalyzed, enantioselective intramolecular oxa-Michael reaction of alcohols to tethered, low electrophilicity Michael acceptors is described. Improved reactivity over previous reports (1 day vs 7 days), excellent yields (up to 99%), and enantiomeric ratios (up to 99.5:0.5 er) are demonstrated. The broad reaction scope, enabled by catalyst modularity and tunability, includes
Bifunctional Iminophosphorane‐Catalyzed Enantioselective Nitroalkane Addition to Unactivated α,β‐Unsaturated Esters
作者:Daniel Rozsar、Alistair J. M. Farley、Iain McLauchlan、Benjamin D. A. Shennan、Ken Yamazaki、Darren James Dixon
DOI:10.1002/anie.202303391
日期:——
The first intermolecular enantioselectiveaddition of nitroalkanes to unactivated α,β-unsaturated esters is described, catalyzed by a bifunctional iminophosphorane (BIMP) superbase. This fundamental synthetically relevant transformation proceeds with high enantiomeric excesses and yields over a wide range of feedstock substrates, providing pharmaceutically relevant building blocks in a single step
Bifunctional Iminophosphorane Catalyzed Amide Enolization for Enantioselective Cyclohexadienone Desymmetrization
作者:Charmaine Y. X. Poh、Daniel Rozsar、Jinchao Yang、Kirsten E. Christensen、Darren J. Dixon
DOI:10.1002/anie.202315401
日期:2024.1.25
The enolization of 2-arylacetamides, followed by an enantioselective intramolecular conjugate addition to tethered 2,5-cyclohexadienones, yielding saturated fused N-heterocycles, is described. The transformation is achieved by employing a bifunctional iminophosphorane (BIMP) superbase catalyst and represents the first unactivated carboxamide deprotonation in a metal-free, catalytic, and enantioselective