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The reactions of 3‐Butyl‐1,2‐diphenylphosphindole with dimethyl acetylenedicarboxylate
Author(s) -
Hughes Alan N.,
Amornraksa Kitti,
Phisithkul Siriporn,
Reutrakul Vichai
Publication year - 1976
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570130112
Subject(s) - adduct , chemistry , dimethyl acetylenedicarboxylate , oxygen atom , molecule , medicinal chemistry , lone pair , organic chemistry , catalysis , cycloaddition
Unlike 1,2,5‐triphenylphosphole, 3‐butyl‐1,2‐diphenylphosphindole reacts smoothly with two molecules of dimethyl acetylenedicarboxylate to give the phosphindole oxide, a yellow adduct and a colourless adduct. The case of the reaction is taken to indicate less lone pair interaction with the π‐system in phosphindoles than in phospholes. The yellow adduct is shown to be a phosphindolium cyclopentadienylide, i.e. an adduct of the phosphindole and two molecules of the ester less one oxygen atom. The colourless adduct is shown to be a 1:2:1 adduct of the phosphindole, the ester and water and has a benzodihydrophosphonin structure. Mechanisms for the formation of both adducts are proposed. Adducts of this general type were previously unknown in organophosphorus chemistry.