Use of olefin templates in queued chemical transformations using late transition metal catalysis. Total synthesis of cis and trans bupleurynol via a single multireaction sequence.

1-Bromo-2-iodoethylene (9) was used as a central, pseudosymmetric building block for the fully convergent and modular synthesis of two related natural products, cis (1a) and trans (1b) bupleurynol. In doing so, a 9-step synthesis of 1a (reported previously) has been vastly truncated to one single operation by using queued cross-coupling reactions with Pd catalysis, negating the need for any protecting group chemistry. Copyright 2004 American Chemical Society