Trifunctionalization of the purine scaffold using Mg and Zn organometallic intermediates.

Starting from an appropriate 6-chloro-2-TMS-purine derivative, a regioselective functionalization of the purine scaffold was achieved successively at positions 8, 6, and 2 via zinc and magnesium intermediates which were generated either by a direct zincation with TMPZnCl·LiCl or by an I/Mg exchange with iPrMgCl.