SYNTHESES OF NITROGEN-HETEROCYCLES BY MEANS OF AMINE-DIRECTED CARBONYLATION AND HYDROCARBONYLATION

Amine-directed carbonylation of 2-allylpiperidine (5) gives 8-methyl-1-azabicyclo[4.3.0]nonan-9-one (7) with extremely high regio- and stereoselectivity, which is promoted by a stoichiometric amount of [RhCl(CO)2]2 in the presence of hydrogen chloride. A catalytic version of this process is developed, which converts 5-benzylamino-1-pentene (9) to 1-benzyl-3-methyl-2-piperidinone (10) selectively. Novel aminocarbocyclization of 9 gives 1-benzyl-3-methylpiperidine (12) or 1-benzylazepane (13) exclusively by employing appropriate hydrocarbonylation conditions. The scope and limitation of these new processes are discussed.