The Configurations of the Alkoxy-1,2-Dibenzoyl-Ethylenes and Related Compounds

Abstract

Recent studies on the cis-and trans-1,2-dibenzoylethylenes and benzalacetophenones (2-4) are of interest in connection with the possibility of assignment of configurations to the alkoxy, aroxy, hydroxy, amino, and alkylaminodibenzoylethylenes (I, II, VIII, IX), and have led to the further work described in this paper.Methoxydibenzoylethylene (I) (5-9), known in only one form, has been regarded (probably correctly) as thermodynamically the more stable of the two possible stereoisomers, and because of this it was considered to be trans (7). However, its synthesis by nitric acid oxidation of the corresponding furan suggests the cis configuration (9, 10).Positive evidence on which to base configurational assignments was sought through study of cases where both stereoisomers could be obtained and compared. 1 The work On which this paper is based is described in ref.(1).

Rich or poor: the impact of electron donation and withdrawal on the photophysical and photocatalytic properties of copper(i) complexes

“…The overall yields were calculated using the attenuation coefficient of DBE ( ε = 18.1 × 10 3 M −1 cm −1 ). 90,91 Additional experiments confirmed the stability of the photosensitizers and DPF under the chosen conditions (ESI† Fig. S11.14–S16), and the necessity for light and the PSs themselves to achieve conversion (ESI† Fig.…”