Pergamon Tetrahedron Letters 39 (i 998) 5281-5284 TETRAHEDRON LETTERS Palladium-catalysed Substitution Reactions of geminal Allylic Diacetates Fanie R. van Heerden,* Johan J. Huyser, D. Bradley G. Williams and Cedric W. Holzapfel Departmentof Chemistry and Biochemistry, Rand Afrikaans University, P.O. Box 524, Auckland Park, 2006, Republic of,South Africa Received 2 April 1998; accepted 12 May 1998 Abstract The Pd(0)-catalysed substitution of allylic 1,1-diacetates by both carbon and oxygen nucleophiles is described. The products isolated resulted from either single or double substitution reactions. © 1998 Elsevier Science Ltd. All rights reserved. Keywords: Palladiumand compounds; allylation; substitution Although geminal allylic diacetates are readily available from the corresponding ot,13- unsaturated aldehydes [1,2], these compounds have received little attention as substrates for palladimn(0)-catalysed substitution reactions. The presence of two allylic leaving groups in these compounds theoretically permits the introduction of two different nucleophiles in two stepwise palladium-catalysed substitution reactions (Scheme 1). Huang and Lu [3] were the first to investigate this reaction, and they found that stabilised carbon nucleophiles attacked the acetate carbonyl which lead to the formation of the aldehyde and unwanted substitution products. In contrast to these results, several groups [4-8] obtained monosubstituted R .... ~.~ OAc Pd(0)~rq.u I r R...~ OACl or Rx ~ OAc OAc Nu Nu1 l R=Ph ~ Pd(O),Nu ? 2 R--H RN~ Nu 2 l Nu Scheme 1 0040-4039/98/$19.00 © 1998 Elsevier Science Ltd. All rights reserved. PIL" S0040-4039(98)01000-4