Synthesis of N ‐Alkenylpurines by Rearrangements of the Corresponding N ‐Allyl Isomers: Scopes and Limitations

N ‐9‐ and N ‐7‐alkenylpurines have been synthesized by rearrangement of the corresponding N ‐allyl derivatives, often in good yields and with high stereoselectivity. Base promoted and transition metal mediated rearrangements have been studied. Simple allylpurines were easily rearranged with catalytic amounts of RuClH(CO)(PPh 3 ) 3 . The efficiency of base promoted rearrangement was highly dependent on the detailed structure of the starting material, but this reaction often occurred with surprisingly high Z ‐selectivity.