Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Org Lett. 2021 Apr 16;23(8):2853-2857. doi: 10.1021/acs.orglett.1c00248. Epub 2021 Mar 26.
A phosphorus(III)-mediated dearomatization of -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 substituent. Notably, the rearrangement adducts underwent rapid and complete reversion to the parent squaraine in the presence of a Brønsted acid.
三价磷介导的取代二苯胺方酸染料的去芳构化反应导致不寻常的骨架重排，提供了具有 C3 侧链的奇异、高度共轭的苯并呋喃酮和吲哚酮骨架，该侧链由烯醇、磷叶立德和 2,4-二取代苯胺的线性燃烧组成。通过实验和计算分析，对机理评估表明，该重排反应显著依赖于苯胺取代基的酸性。值得注意的是，在布朗斯台德酸的存在下，重排加成物迅速且完全反转回母体方酸。
