Synthesen und Ringerweiterungsreaktionen von 2‐(4‐Hydroxyalkyl)‐2‐nitrocycloalkanonen

Abstract

Syntheses and Ring‐Enlargement Reactions of 2‐(4‐Hydroxyalkyl)‐2‐nitrocycloalkanones Syntheses of the title compounds were achieved by [Pd{P(C 6 H 5 ) 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 NaBH 4 reduction or methylation with (CH 3 ) 2 Ti(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.