ChemInform Abstract: Studies on the Carbon Zip Reaction of 2-Oxocycloalkane-1-carbonitriles.
Abstract
The formation of ring-enlarged products (II) from the title compounds (I) is influenced both by the lengthof the side chain and by the size of the ring system [8- and 12-membered Substrates; the CN group acts as a charge stabilizer in the course of the ring opening step of the alkoxide intermediate analogous to (VI)].
ChemInform Abstract
The formation of ring-enlarged products (II) from the title compounds (I) is influenced both by the lengthof the side chain and by the size of the ring system [8- and 12-membered Substrates; the CN group acts as a charge stabilizer in the course of the ring opening step of the alkoxide intermediate analogous to (VI)]. Competing reactions give (III) (retro-Michael reaction), (IV) (transesteri?cation), (V) and (VI) (diastereomers of uncertain stereochemical assignment). Generally speaking, the 8-membered compounds show a higher tendency to undergo ring enlargement; accordingly, the methyl ketone (VIIa) yields the desired product (VIII) whereas (VIIb) fails to react with tBuOK. [Detailed description of the influence of different reaction conditions on product distributions and of the preparation of the Starting materials (I) and (VII) from (III)].
