Novel reactions of 6,7-dimethoxy-3,4-dihydroisoquinoline and 3,4-dihydro-β-carboline with dipolarophiles

New reactions of 6,7-dimethoxy-3,4-dihydroisoquinoline and 3,4-dihydro-β-carboline with various electron-deficient olefins are described. 'One-pot' generation and cycloaddition of the 1,3- and 1,4-dipoles formed from these heterocycles with a range of alkene dipolarophiles affords cycloadducts in good yields with high regio- and stereoselectivity.