While conformationally favourable thiocarbamates bearing an aromatic methoxy group undergo intramolecularipso-substitution of the methoxy group by treatment with tris(trimethylsilyl)silane (TTMSS) and AIBN, either conformationally flexible or favourable ketones easily cyclise into a five- or six-membered rings by treatment with SmI2.
Alkyl radicals generated by treatment of thiocarbamates of conformationally favorable 3-alkyl-3-arylpropan-1-ols with tris(trimethylsilyl)silane and AIBN efficiently undergo intramolecular ipsosubstitution of the methoxy group, yielding the corresponding cyclized products. In contrast, either conformationally favorable or flexible 1-arylalkan-3- or 4-ones easily cyclize into five- or six-membered