| Abstract: | Syntheses and Ring-Enlargement Reactions of 2-(4-Hydroxyalkyl)-2-nitrocycloalkanones Syntheses of the title compounds were achieved by Pd{P(C6H5)3}4]-catalyzed reaction of 2-nitrocycloalkanones 3 with vinyloxirane followed by catalytic hydrogenation. By another route, the known methyl 4-(1-nitro-2-oxocycloalkyl)butanoates 6 were reduced to the corresponding aldehydes 7 which by NaBH4 reduction or methylation with (CH3)2Ti(i-Pr)2 were transformed to the alcohols 5 and 8 , respectively (Saheme 1). Treatment of 5 and/or 8 with KH/THF under reflux gave, via a 7-membered intermediate, the nitrolactones 12 and oxolactones 13 (Scheme 3). Compared with similar reactions running via 5- or 6-membered intermediates (see 1 and 2 ), the yields are distinctly lower. The natural occurring 12-tridecanolid ( 14 ) was synthesized. |
