(and in some cases rhodium) catalysed regiospecific 5-exo-, 6-endo-and 6-exo-trig cyclisations of aryl iodides and vinyl bromides onto proximate alkenes or heteroaromatic rings (indole, pyrrole) lead to a wide variety of fusedring systems. In appropriate cases the methodology provides a facile approach to the creation of tetrasubstituted carbon centres. Double bond isomerisation in the product is only
Palladium-catalyzed cyclization of 2-heteroyl-1-methylene-1,2,3,4-tetrahydroisoquinolines. Studies on 6-endo- versus 5-exo-trig cyclization
作者:Agnès Bombrun、Olivia Sageot
DOI:10.1016/s0040-4039(96)02511-7
日期:1997.2
In this paper we report our studies on 6-endo- versus 5-exo-trigcyclizations of 2-heteroyl-1-methylene-1,2,3,4-tetrahydroisoquinolines. This can be used for the construction of a variety of functionalized five- or six-membered heterocyclic rings.
Various N-vinyl- and N-allyl-amides of 2-iodobenzoic acid undergo catalytic cyclisation in the presence of tetraethylammonium chloride and a palladium acetate-based catalyst system to generate a range of synthetically useful structural features including tetrasubstitutedcarboncentres, and spiro- and bridged-ringcompounds, and in which 5-exo-trig cyclisations are kinetically favoured.