In situ tandem allylic acetate isomerisation-ring closing metathesis: 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene ruthenium benzylidenes and palladium(0)-phosphine combinations

The use of 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene ruthenium benzylidenes as olefin metathesis pre-catalysts in conjunction with palladium(0) phosphine combinations allows tandem in situ allylic acetate isomerisation ring closing metathesis reactions to occur. The tandem reaction can either be performed on separate substrates in the same pot, or on substrates containing both allylic acetate and diene functionality. (C) 2002 Elsevier Science Ltd. All rights reserved.