Photoaddition of biacetyl and alkenes. Reaction stereochemistry, multiplicity, and photokinetics

Abstract

Photolysates were concentrated on a rotary evaporator and the residues chromatographed (Silica Gel, 2.5 X 40 cm) and eluted with 0-30% benzene in hexane. Eluted fractions were analyzed by GLPC.Quantum Yields. Potassium ferrioxalate and the procedure described by Calvert and Pitts were used.32 The light source was a 200-W Hg-Xe lamp, and the 405-nm line was isolated by a Jarrell-Ash monochromator.The light intensity was determined twice before and once after the actual photolysis. No change in light intensity was detected during these experiments. The photolysis of 1 and DCA were carried out to ~10% conversion of 1. The photolysate was analyzed by GLPC using an internal standard and determination of GLPC response factors. The quantum yields were determined three times. The photooxygenation of 1 was used as an actinometer for the measurements of the quantum yields for the photooxygenation of 12, 14, and 18, which were irradiated on the merry-go-round.

Photoreactions of biacetyl with electron‐rich olefins. An extended mechanism

“…Both methods yielded the same results. Acetyl-endo-7-methyl-2,4,6-trioxabicyclo~3.2.0 6,2a+),71 (8.9),43 (100,CH,CO+). C7HIO04 (158.2) Calcd.…”

Photochemical inactivation of Aeromonas aminopeptidase

“…The photochemistry of BD is relatively well known [7][8][9][10][11], but the photochemical aspects have been largely ignored by enzyme and protein chemists who have exploited BD as a specific reagent of the active arginyl residues of enzymes. These results thus suggest that most of the previous arginine modification studies with BD and related a-diketones should be repeated by considering the photochemical and photophysical aspects involved.…”

Steady state and laser flash photolysis of acenaphthenequinone in the presence of olefins

“…detailed mechanistic study of its reaction with a number of olefins has appeared. 8 Biacetyl undergoes oxetane formation with ethenes and the regioselectivity is generally higher than that observed in the corresponding reactions of monoketones.…”