Highly Regio- and Stereoselective Dirhodium Vinylcarbene Induced Nitrone Cycloaddition with Subsequent Cascade Carbenoid Aromatic Cycloaddition/NO Cleavage and Rearrangement
作者:Xiaochen Wang、Quentin M. Abrahams、Peter Y. Zavalij、Michael P. Doyle
DOI:10.1002/anie.201201917
日期:2012.6.11
An abnormal cascadeprocess provides a selective method for the preparation of tricyclic heterocycles. The cascade involves a metal carbene induced regioselective [3+2] cycloaddition, a Buchner reaction, and a [1,7]‐oxygen migration, which occurs with NO cleavage (see scheme). The products are formed with remarkable specificity.
Enoldiazosulfones for Highly Enantioselective [3 + 3]-Cycloaddition with Nitrones Catalyzed by Copper(I) with Chiral BOX Ligands
作者:Frady G. Adly、Kostiantyn O. Marichev、Joseph A. Jensen、Hadi Arman、Michael P. Doyle
DOI:10.1021/acs.orglett.8b03421
日期:2019.1.4
undergo [3 + 3]-cycloaddition with nitrones when catalyzed by copper(I) catalysts, but not with dirhodium(II) catalysts. Under mild reaction conditions with chiral bisoxazoline ligands, copper(I) catalysts produce 1,2-oxazine-sulfone derivatives in high yields and enantioselectivities. Dirhodium(II) catalysts form stable donor–acceptor cyclopropenes that undergo uncatalyzed [3 + 2]-cycloaddition reactions
A donor–acceptor cyclopropene as a dipole source for a silver(i) catalyzed asymmetric catalytic [3+3]-cycloaddition with nitrones
作者:Xinfang Xu、Peter J. Zavalij、Michael P. Doyle
DOI:10.1039/c3cc46415f
日期:——
Silver(I)-catalyzed asymmetric formal [3+3]-cycloaddition of nitrones with a donor-acceptor cyclopropene, formed in situ from dirhodium acetate-catalyzed dinitrogen extrusion/intramolecular cyclization of enoldiazoacetates, effectively generates 3,6-dihydro-1,2-oxazine derivatives in high yield and with exceptional stereocontrol.
Chiral tris(oxazoline)/Cu(I) complexes are demonstrated as a type of efficient catalysts for the asymmetric Kinugasa reaction of terminal alkynes with C-arylnitrones, providing a highly enantio- and diastereoselective access to optically active beta-lactams. (C) 2012 Elsevier Ltd. All rights reserved.