A new route to famciclovir via palladium catalysed allylation

An efficient route to the acyclic nucleoside analogue famciclovir has been developed based on a palladium(0) catalysed coupling of 2-amino-6-chloropurine and an allylic carbonate sidechain derived from 2,2-dimethyl-1,3-dioxan-5-one, The reaction proceeds via a highly N-9 regioselective purine allylation step involving a novel palladium mediated N-7 to N-9 rearrangement. (C) 2000 Elsevier Science Ltd. All rights reserved.