Selenium dioxide oxidations of olefins. Trapping of the allylic seleninic acid intermediate as a seleninolactone

Abstract

kn/kr, = 1.65 (50 cal/D).5 In the case of the terminal bromoallene, Id, kH/kD = 1.23 (44 cal/D) for CD3 substitution at C-3 in 70T at 60°. These data strongly support the proposal that terminal haloallenes as well as trisubstituted haloallenes react via charge-delocalized cationic intermediates under initially neutral conditions. The «-secondary isotope effect observed upon deuterium substitution at the reaction center /cH//cD = 1.22 represents one of the largest «-secondary isotope effects yet reported. For saturated chlorides, such as 1-(5) V.

Abnormal reactions of 2‐methoxy‐4,9‐dimethyl‐1‐nitroacridine with selenous acid and selenium(IV) oxide. Synthesis of 1H‐selenopheno[2,3,4‐k,l]acridine‐1‐one: A new seleno‐containing ring system

“…In a similar manner, H 2 SeO 3 oxidizes alkenes to allylic alcohols [4,5]. If the intermediate C is turned to aldehyde 11 via a loss of HSeOH, the reduced selenium species generated by this pathway could further act as a nucleophile.…”

Synthesis and Algicidal Activity of (+)-Cyanobacterin and Its Stereoisomer

“…When Z-olefin 9 was treated with 3.6 equivalent of selenium dioxide in dioxane at 80 C, (+)-1a and its epimer at 5-C (1b) were obtained in a ratio of 1a:1b = 12:82 in 41% combined yield. A mechanism for the selenium dioxide-mediated allylic oxidation was first proposed by Sharpless et al, 17,18) in which two consecutive pericyclic reactions, an initial ene reaction followed by a [2,3]-sigmatropic shift, are involved. Recently, the stereochemical aspects of the initial ene reaction and the whole reaction were clarified by a kinetic isotope effect study 19) and an ab initio study 20) respectively.…”

The Course of the Catalytic Hydrogenation/Isomerization Reaction of Steroidal Ring B Olefins in the 13β‐ and 13α‐Series

“…-IR. : 3590,1725,1450,1435,1405,1375,1356,1318,1288,1135,1122,1090,1078,1065,22) For a mechanistic proposal of the allylic Se02 oxidation see [23]. 23) An analytical sample was chromatographed on silicagel with benzene/ethyl acetate 4: 1 and recrystallized from acetone.…”