Photoinduced molecular transformations. Part 119. Photochemical nitrogen insertion into bicyclo[2.2.1]heptanones; the photochemistry of oximes of (+)-fenchone and (+)-camphor

Abstract

The photolysis of the oxime of (+)-fenchone in methanol gave a 1:1 ratio of two isomeric lactams, 1,4,4-trimethyl-2-azabicyclo[3.2.1]octan-3-one (13%) and its previously undescribed isomer, 1,4,4-trimethyl-3-azabicyclo[3.2.1]octan-2-one (13%), with the accompanying formation of alkenoic acid amides (10%). Photolysis of the oxime of (+)-camphor in methanol similarly gave two isomeric lactams, 1,8,8-trimethyl-2-azabicyclo[3.2.1]octan-3-one (α-camphidone)(12%) and 1,8,8-trimethyl 3-azabicyclo[3.2.1 ]octan-2-one (12%), in a 1:1 ratio, as well as an alkenoic acid amide (α-campholenic amide)(32%). Nitriles arising from photochemical α-fission were obtained, in 11 and 6% yield, through photolysis of the respective oximes. Therefore, methyl groups attached to the α-carbons had little affect on the direction of the photoreaction of bicyclo[2.2.1]heptanone oxime. 2-and 3-Azabicyclo[3.2.1]octanones can thus be synthesized by the photoreaction of bicyclo[2.2.1]heptanone oximes, which can be carried out without the use of any other reagent.