Photoenolization of o-Methylvalerophenone Ester Derivative.

Abstract:

:Photolysis of ester 1 in argon-saturated methanol and acetonitrile does not produce any product, whereas irradiation of 1 in oxygen-saturated methanol yields peroxide 2. Laser flash photolysis studies demonstrate that 1 undergoes intramolecular H atom abstraction to form biradical 3 (λmax ~340 nm), which intersystem crosses to form photoenols Z-4 and E-4 (λmax ~380 nm). Photoenols 4 decay by regenerating ester 1. With the aid of density functional theory calculations, it was concluded the photoenol E-4 does not undergo spontaneous lactonization or electrocyclic ring closure because the transition state barriers for these reactions are too large to compete with reketonization of E-4 to form 1.

journal_name

Photochem Photobiol

authors

Das A,Lao EA,Gudmundsdottir AD

doi

10.1111/php.12590

subject

Has Abstract

pub_date

2016-05-01 00:00:00

pages

388-98

issue

3

eissn

0031-8655

issn

1751-1097

journal_volume

92

pub_type

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