β-Fisson of 9-Decalinoxyl Radicals: Reversible Formation of 6-Ketocyclodecyl Radical

Article abstract of DOI:10.1021/jo00172a051

Rearrangement at 0 deg C of trans-9-decalinyl hypobromide (1_trans, X=Br), formed by interaction of 1_trans (X=H) with bromine and silver acetate or mercuric oxide, gives 6-bromocyclodecanone(4, X=Br) whereas the same reaction at 81 deg C gives 2-(4-bromobutyl)cyclohexanone (6, X=Br).The cis isomer (1_cis, X=Br) behaves similarly.The relative yields of the nitroso dimers, 11, 12, and 13, formed by photolysis of 1_cis (X=NO) and 1_trans (X=NO), also depend on the reaction temperature.Reduction of 6-bromocyclodecanone (4, X=Br) with tribytylstannane in high concentration gives mainly cis- and trans-9-decalinol, with the former predominating.These results indicate (i) that 9,10-bond fisson of the 9-decalinoxyl radicals, 2_cis and 2_trans, is rapid but reversible, (ii) that 1,9-bond fisson of 2_cis and 2_trans is relatively slow and is essentially irreversible under the conditions used here, and (iii) that ring closure of the radical (5) favors formation of the cis product (2_cis).