Abstract
Recently we reported an efficient synthesis of the berbine alkaloids3,4 by the use of the bromo esters5 prepared from 3-isochromanones. Now a new general synthetic route to the berbine alkaloids beginning with the condensation of the phenethylbromide 3 and 3-(2H) isoquinolone 2 is being described. The method gains added advantage of placing desired substitution on both rings A and D of the berbine, emerging from the easy availability of the starting compounds. In conclusion, the present results have not only added one more efficient example to more than a dozen successful procedures of the berbine synthesis6 but also offer a potential route to the structurally parallel indoloquinolizidine alkaloids.