A. Bashirhashemi et al., REGIOSELECTIVITY IN PHOTOCHEMICAL CHLOROCARBONYLATION OF CARBONYL-COMPOUNDS, Journal of organic chemistry, 59(8), 1994, pp. 2132-2134
Photochemical chlorocarbonylation of a series of cyclic and acyclic ca
rbonyl compounds shows remarkable regioselectivity and gives beta- or
gamma-substituted products in reasonable yields. Irradiation of cyclop
entanone in oxalyl chloride followed by esterification with methanol g
ave methyl 3-oxocyclopentanecarboxylate (4). Similarly, photochemical
chlorocarbonylation of cyclobutanone yielded methyl 3-oxocyclobutaneca
rboxylate (6). Application of the chlorocarbonylation reaction to 3-pe
ntanone gave methyl 4-oxohexanoate (8) and dimethyl 4-oxopimelate (9).
When a mixture of 3-methylbutanoic acid and oxalyl chloride was irrad
iated, dimethyl 3-methylglutarate (11) was obtained after methanolysis
. A kinetically-controlled mechanism for the photochemical process was
deduced.