Substituent effects in samarium diiodide-induced 6-trig cyclizations of gamma-arylketones to functionalized hexahydronaphthalene derivatives

The samarium diiodide-induced 6-trig cyclizations, of Substituted gamma -ar ylketones 1. 4, 5, 9, 11. and 14 are strongly influenced by substituents of the aryl group. Whereas para-methoxy derivative 5 as well as ortho- and pa ra-cyano derivatives 9 and 14 provided the expected functionalized hexahydr onaphthalene derivatives 6 (together with 7). 10, and 15 in moderate to goo d yields. ortho-methoxy Compound I was a poor substrate and meta-methoxy de rivative 4 did not undergo cyclization at all. The behavior of meta-cyano c ompound 11 was exceptional since the intermediate cyclohexadienyl "carbanio n" was sufficiently stable to be trapped by electrophiles furnishing adduct s such as 17 and 18 in moderate yields.