Cycloaddition reactions of allenes with N-phenylmaleimide. A two-step, diradical-intermediate process
作者:Daniel J. Pasto、Peter F. Heid、Steven E. Warren
DOI:10.1021/ja00377a022
日期:1982.6
e process. The stereochemical features controlling the formation of the stereoisomeric diradical intermediates and their ring closures are discussed. In addition to the cycloaddition processes, competitive ene reactions occur to produce intermediate dienes, which react further to produce 1:2 adducts or nonreactive alkyne-containing 1:1adducts. These ene reactions also appear to proceed via diradical
Metal catalysis in organic reactions. Part 13. The reaction of 3-en-1-ynes with trialkylalanes: influence of transition-metal complexes
作者:Anna Maria Caporusso、Giampaolo Giacomelli、Luciano Lardicci
DOI:10.1039/p19810001900
日期:——
The reaction between trialkylalanes and 3-alkyl-, 4-alkyl-, or 3,4-dialkyl-but-3-en-1-ynes (1) leads to products which correspond to metallation, reduction, and carbalumination processes. The extent of such reactions, and the regio- and stereo-selectivity of the carbalumination, are dependent on the enyne used. A mechanism is proposed involving tautomeric equilibria among several α-unsaturated organoaluminum
An asymmetric intermolecular [4 + 2] cycloaddition of 1,3-dienes with dialkyl acetylenedicarboxylates, which was catalyzed by a rhodium(i)-chiral phosphoramidite complex, was developed. This protocol provided a highlyenantioselective access to prepare carbonyl substituted cyclohexa-1,4-dienes with up to 96% yield and >99% ee. Notably, a cycloaddition on the 10 g scale gave the product in 92% yield