Asymmetric synthesis of isoquinoline alkaloids

Abstract

The use of chiral formamidines affixed to variously substituted tetrahydroisoquinolines, allows asymmetric C-C bond forming reactions to occur α- to the amino group. In this manner, a wide variety of (S)-1-alkyl-1,2,3,4-tetrahydroisoquinolines were constructed in > 90% enantiomeric excess. Choosing the proper substituents and skeletal features, an efficient entry into the benzylisoquinoline, tetrahydroprotoberberine, aporphine, and isopavine class of alkaloids was achieved.