Asymmetric Catalytic [4 + 2] Cycloaddition via Cu–Allenylidene Intermediate: Stereoselective Synthesis of Tetrahydroquinolines Fused with a γ-Lactone Moiety
A decarboxylative formal [4 + 2] cycloaddition reaction between ethynyl benzoxazinanones and 5-substituted 2-silyloxyfurans catalyzed by chiral Cu–Pybox complex is described. This method allows the formation of intriguing tetrahydroquinolines fused with a butyrolactone moiety featuring three contiguous chiral centers in high yields with excellent diastereo- and enantioselectivities in most cases. The
The Oxidative Mannich Reaction Catalyzed by Dirhodium Caprolactamate
作者:Arthur J. Catino、Jason M. Nichols、Brian J. Nettles、Michael P. Doyle
DOI:10.1021/ja061146m
日期:2006.5.1
Dirhodium caprolactamate [Rh2(cap)4] is a highly effective catalyst for the oxidative Mannich reaction. The reaction proceeds via C-H oxidation of a tertiary amine followed by nucleophilic capture. This green transformation is conducted in protic solvent using inexpensive T-HYDRO (70% t-BuOOH in water). Synthetically valuable gamma-aminoalkyl butenolides are obtained.
Highly efficient Cu-catalyzed oxidative coupling of tertiary amines and siloxyfurans
A mild, selective, and efficient protocol for the synthesis of gamma-aminoalkyl butenolides via the oxidative coupling between tertiary amines and siloxyfurans catalyzed by simple copper salts was developed. Compared with the reported method, our method employs copper catalyst instead of the expensive rhodium catalyst. Besides TBHP, both O-2 and H2O2 can also be utilized as oxidant to effect the coupling. (C) 2008 Elsevier Ltd. All rights reserved.