Dimethyldioxirane and Acetone Are Not in Equilibrium

Abstract

The potential transfer of an oxygen atom from dioxiranes to a ketonic carbonyl group is disproved by appropriate D-and 13 C-labelling. As shown by 13 C NMR spectroscopy bis(trideuteriomethyl)dioxirane and [carbonyl-13 C]acetone are not

Three‐Membered Heterocycles. Structure and Reactivity

“…A more common outcome is the amination of active methylene groups. Thus, treatment of barbituric acid (805) with oxaziridine 800 in a medium of dilute sodium hydroxide led to the production of the 5-aminobarbituric acid (806) in 78% yield [787]. Similarly, deprotonation of phenylacetonitrile 807 with lithium hexamethyldisylazide (LiHMDS), followed by treatment with oxaziridine 802, provided the Boc-protected benzylamine 808 in 46% yield [785].…”

“…Toward this end, dilute solutions of dimethyldioxirane (DMD) are available by treating acetone with Oxone in an aqueous bicarbonate buffer at low temperature, after which the dioxirane is distilled at reduced pressure (Scheme 2.119). The distillate so-obtained contains about a 0.1 M solution of DMD in acetone (towards which the dioxirane is stable [806]), and this is usually titrated before use [807,808]. The dilution factor can be inconvenient [809], although some practical modifications have been disclosed [810,811], including phase-transfer conditions, which can be applied even to large-scale preparations [812].…”

C-Acylations of Polymeric Phosphoranylidene Acetates for C-Terminal Variation of Peptide Carboxylic Acids

“…Oxidative cleavage − of 4a employing dimethyldioxirane in acetone afforded the peptidyl 4-amino-2,3-dioxo-butanoates (“peptidyl diketoesters”) 5 (Scheme 2). To our knowledge, this novel class of compounds has not been described in the literature so far.…”

Reactions of Aldehydes and Ketones and their Derivatives

“…335 NMR experiments using 2 H-and 13 C-labelled substrates indicate that acetone and dimethyloxirane are not in equilibrium. 336 de Thioketones such as 4,4 -dimethoxythiobenzophenone react with enantiopure (R)-2-vinyloxirane to give virtually enantiopure (S)-4-vinyl-1,3-oxathiolanes (86) in high ee yield, using mild Lewis acid conditions (SiO 2 , DCM, 0 • C). 337 More hindered thioketones require a stronger Lewis acid (BF 3 , −78 • C).…”