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Diels–Alder reactions of directly C3-dieneylated chlorophyll derivatives

Author:
Funayama, Naoya, Tamiaki, Hitoshi
Source:
Tetrahedron letters 2019 v.60 no.1 pp. 63-67
ISSN:
0040-4039
Subject:
absorption, chemical structure, chlorins, chlorophyll, cycloaddition reactions, methylene chloride, naphthoquinones, oxidation
Abstract:
The [4π + 2π] cycloaddition of methyl 3-(1,3-butadien-1/2-yl)pyropheophorbides-a with tetracyanoethylene, dimethyl acetylenedicarboxylate, and naphthoquinone gave the corresponding Diels–Alder reaction adducts. The trans-1-substituted 1,3-butadiene was more reactive than its regioisomeric 2-substituent. The oxidation of some cycloadducts gave C3-arylated chlorophyll derivatives, whose ortho-substitution blue-shifted the corresponding Qy absorption maxima in dichloromethane because of the steric repulsion between the aryl and chlorin π-planes.
Agid:
6232199