New beta-carboline derivatives by double-cyclization of chiral alpha-heteroarylmethylamino esters

Dialkylation of amino eaters 2 with o-bromo-bromomethylheteroaromatics 1 an d double-cyclization of the resulting N,N-disubstituted esters 3 via bromo- lithium exchange to tetrahydropyridine rings gives access to dicondensed 5- hydroxy-1-azabicyclo[3.3.1] nonanes 4, mostly beta-carboline derivatives. T he synthesis is highly stereoselective affording optically active products.