REACTIONS OF N-ACYLAZIRIDINES WITH SODIUM METAL AND SODIUM NAPHTHALENIDE - ELIMINATION OF OLEFINS

Reactions of N-acylaziridines 1a-g (N-benzoyl except 1d) with sodium o r naphthalenide N-.- in THF provide a variety of products that usually arise via the aziridino ketyls 2. Homolytic ring opening of 2 generat es the amidatoalkyl radicals 3. Only with a very short reaction time w ere small amounts of benzil or benzoylnaphthalenes obtained indicating a reversible trapping of 2 by dimerization or coupling with N-.-. Hom olysis of 2 produced always the more stable 3 apart from reactions of monomethylaziridines 1c,d where the primary radical i-3c,d is kinetica lly favoured. The amides R(1)CONHCHR(4)CHR(2)R(3) (9: isopropylamides i-9c,d from 1c,d) were usually the main products. 9 arise from 3 eithe r by H atom abstraction from THF (probably in sodium metal runs) or by reduction of 3 to carbanions 5 that abstract a proton from THF (N-.- runs). Addition of 5a (R(2-4) = H) to 1a gives finally the ketone 8a. Self reaction of primary radical 3a is dimerization. Self reaction of tertiary or secondary radicals is disproportionation when an allylamid e arises. This isomerizes to an enamide unless it is conjugated. R(2)R (3)C=CHR(4) and R(1)CONH(2) arise (probably) always. The mechanism, po ssibly a cyclic process of anion 6, is not clear.