Open AccessA Phosphine-Mediated Dearomative Skeletal Rearrangement of Dianiline Squaraine Dyes
Author(s) -
Emily P. Bacher,
Kevin J. Koh,
Antonio J. Lepore,
Allen G. Oliver,
Olaf Wiest,
Brandon L. Ashfeld
Publication year - 2021
Publication title -
organic letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.94
H-Index - 239
eISSN - 1523-7060
pISSN - 1523-7052
DOI - 10.1021/acs.orglett.1c00248
Subject(s) - chemistry , substituent , aniline , ylide , phosphine , adduct , conjugated system , medicinal chemistry , phosphine oxide , organic chemistry , catalysis , polymer
A phosphorus(III)-mediated dearomatization of ortho -substituted dianiline squaraine dyes results in an unusual skeletal rearrangement to provide exotic, highly conjugated benzofuranone and oxindole scaffolds bearing a C3 side chain comprised of a linear conflagration of an enol, a phosphorus ylide, and 2,4-disubstituted aniline. Employing experimental and computational analysis, a mechanistic evaluation revealed a striking dependence on the acidity of the aniline ortho substituent. Notably, the rearrangement adducts underwent rapid and complete reversion to the parent squaraine in the presence of a Brønsted acid.