Pictet-Spengler condensation of N-sulfonyl-β-phenethylamines with α- chloro-α-phenylselenoesters. New synthesis of 1,2,3,4- tetrahydroisoquinoline-1-carboxylates

Article abstract of DOI:10.1016/S0040-4039(99)00958-2

The reaction of N-sulfonyl-β-phenethylamines with α-chloro-a- phenylseleno acetate/propionate esters under Lewis acid promotion gives moderate to good yields of the corresponding 1,2,3, 4- tetrahydroisoquinoline-1-carboxylates. Varying degrees of diastereoselection were obtained using chiral sulfonamides and/or esters. Employing this strategy, the achievement of a new total synthesis of Calycotomine is reported.