The first use of phosphahelicene in enantioselective organocatalysis is reported. New chiral phosphahelicenes have been prepared and enable highly enantioselective [3+2] cyclization reactions between arylidene‐ or alkylidenemalononitriles and γ‐substituted allenoates or cyanoallenes. These reactions afford cyclopentene derivatives in both high yields and diastereoselectivities, with enantiomeric excesses
Allenes. Part XX. The preparation of 3-alkyl- and 3,3-dialkylallenenitriles
作者:P. M. Greaves、S. R. Landor、D. R. J. Laws
DOI:10.1039/j39680000291
日期:——
3-Alkyl- and 3,3-dialkylallenecarbonitriles are conveniently prepared in good yield from 1-alkyl and 1,1-dialkyl-3-bromoallenes by the action of cuprous cyanide in NN-dimethylformamide at 35–60° for 2 hours. Tertiary acetylenic alcohols may be directly converted into 3,3-dialkylallenecarbonitriles by stirring for 3 days with potassium cyanide, cuprous cyanide, and hydrobromic acid. The same mixture
Novel synthesis of imidazolines and imidazoles by Michael addition to allenic or acetylenic nitriles
作者:Zacharias T. Fomum、Phyllis D. Landor、Stephen R. Landor
DOI:10.1039/c3974000706a
日期:——
The synthesis of imidazolines and imidazoles by double Michael addition of ethylene- or phenylene-diamines to allenic or acetylenic nitriles is described; enaminicnitriles from α-amino-acids, -esters, and -nitriles did not give pyrrolone derivatives.