Regioselective Addition of Grignard Reagents to a 2-Oxopurinium Salt.

Abstract Treatment of 6-ethoxy-1,3,6,7-tetrahydro-1,3,7-tribenzyl-2 H -purin-2-one with trimethyl-chlorosilane gave a stable tribenzylated 2-oxopurinium salt, which selectively added Grignard reagents in the 6-position. The structure of the adducts were established from long range HETCOR NMR experiments.