On the use of tandem allylic acetate isomerisation and ring-closing metathesis with palladium(0) phosphine complexes and ruthenium benzylidenes as orthogonal catalysts

Attempted tandem allylic acetate isomerisation and ring-closing metathesis using combinations of palladium(0)/Grubbs' catalyst/PPh3 led to either ally lic isomerisation or ring-closing metathesis but not both in tandem. The ef fect was traced to deactivation of Grubbs' catalyst by added PPh3 and poiso ning of the Pd(0) by the necessarily released PCy3 (Cy=cyclohexyl) from Gru bbs' catalyst. Successful tandem isomerisation/ring-closing metathesis was achieved by the use of palladium(0)/PPh3 systems in conjunction with a PCy3 free olefin metathesis catalyst. (C) 2001 Elsevier Science Ltd. All rights reserved.