The Effect of Solvent on Competing Hydroperoxide and Dioxetane Formation on Photo‐Sensitized Oxygenation of Olefins

Abstract

SummaryThe rates of the competitive photo-sensitized oxygenation of 2-isobutylideneadamantane (1) and 2-propylidene-adamantane (2) with 1, I-di-t-butyl-2-methoxyethane (3) in various solvents were determined. The rates for 1 and 2 were independent of solvent, whereas that for 3 varied markedly with solvent polarity, Compounds 1 and 2 gave only hydroperoxides while 3 gave dioxetane. These results are interpreted in terms of two competing processes involving little and much charge separation leading to hydroperoxide and dioxetane, respectively.Although information is sparse, it appears that the nature of the solvent has a negligible effect on the rates of photo-oxygenation of those olefins which give exclusively either allylic hydroperoxides

A Highly Diastereoselective Dioxetane Formation by the Hydroxy-Directed [2+2] Cycloaddition of Singlet Oxygen to a Chiral Allylic Alcohol

“…The relative configurations of the dioxetanes threo - 2a and erythro - 2a were determined by comparison with authentic erythro - 2a , which was synthesized as shown in Scheme . The allylic hydroperoxide 6 was prepared as described and the trans configuration of its double bond was confirmed by the large coupling constant between the olefinic protons ( 3 J = 15.9 Hz). The epoxidation of the achiral hydroperoxide 6 with m CPBA yielded the racemic epoxide 7 , which on base-catalyzed cyclization afforded exclusively the erythro - 2a dioxetane (cf.…”

Singlet Oxygen: Discovery, Chemistry, C60‐Sensitization†

“…Path 1, concerns a supra-antara [2 s +2 a ] (66,74) attack of 1 O 2 in a concerted mode. However, a step-wise dipolar or biradical mechanism (path 3, 2) was supported by computation (75)(76)(77)(78)(79)(80), as well as experimental work (40,41,(81)(82)(83)(84)(85)(86)(87)(88)(89)(90).…”