Photochemical Chlorocarbonylation of HCTD by Oxalyl Chloride. Carbocation-Mediated Rearrangement of HCTD Derivatives to Novel, Substituted Heptacyclopentadecanes
journal contributionposted on 21.10.1998, 00:00 authored by Alan P. Marchand, Sulejman Alihodžić, Bishwajit Ganguly
Photochemical chlorocarbonylation of heptacyclo[18.104.22.168.2,60.3,130.4,1105,9.010,14]tetradecane (“HCTD”, 1), performed by irradiating a solution of oxalyl chloride and 1 in benzene, followed by reaction of the crude reaction product with methanol, afforded a mixture of methyl 1- and 7-(HCTD)carboxylates (i.e., 2 and 3, product ratio 2/3 = 3:1). Reduction of the mixture of cage esters thereby obtained with LiAlH4 afforded the corresponding cage alcohols (4 and 5, respectively), which could be separated via column chromatographic methods. Subsequently, 4 and 5 were converted into the corresponding cage tosylates (i.e., 7 and 13, respectively). Reaction of 7 with CF3CO2H−CHCl3 resulted in solvolysis with concomitant skeletal rearrangement, thereby affording 8a. The corresponding reaction performed by starting with cage tosylate 13 also resulted in solvolysis with accompanying skeletal rearrangement, thereby affording 18a.