Tetrahedron Letters,Vo1.30,No.35,pp 4669-4672,1989 0040-4039/89 $3.00 + .OO Printed in Great Britain Pergamon Press plc ALLYL ETHYL CARBONATE /PALLADIUM (0), A NEW SYSTEM FOR THE ONE STEP CONVERSION OF ALCOHOLS INTO ALLYL ETHERS UNDER NEUTRAL CONDITIONS R. LAKHMIRI, P. LHOSTE and D. SINOU * Laboratoire de Synthbse Asymetrique, associe au CNRS, Universite Claude Bernard, 43, boulevard du 11 Novembre 1918,69622-Villeurbanne Cedex, France. Abstract : Alcohols are converted in a one-step procedure into ally1 ethers under neutral conditions, using ally1 ethyl carbonate in the presence of a catalytic amount of palladium (0). Anomeric hydroxyls are selectively allylated in the presence of other hydroxyl groups. Ally1 groups have been found to be of general use as temporary hydroxyl-protecting groups in sugar che- mistry l-3. The successful application of the ally1 group in carbohydrate chemistry is mainly due to its relative stability during glycosidation or deblocking procedures which lead to the removal of other protecting groups. An ally1 ether can be synthesised by treatment of a free hydroxyl group with 3-halopropene in the presence of base 1. Compounds containing base labile groups can be allylated using allyltrichloro-acetamidate 4. Allylation of alcohols or polyols is also feasible starting from intermediate trialkyltin oxides or dialkylstannylidenes 5; in the latter case, specific monoalkylation of carbohydrates has been observed 6,7. More recently, a neutral two-step allylation procedure was introduced by Guitx? 8 and developed by Tsuji 9 in which an allylcarbonate obtained from an alcohol was subjected to palladium(O) catalyzed decarboxylation to afford an ally1 ether derivative.This procedure has also been applied in carbohydrate chemistry lop1 1. During our programme directed towards the application of organometallic reagents in carbohydrate chemistry, we found that a neutral one-step allylation procedure involving alcohols and especially carbohydrates was possible, using ally1 ethyl carbonate 1 as the allylating reagent in the presence of a catalytic amount of palladium (0) (eq. 1). R-OH CH2=CH-CH2OC02Et zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONM 1 > R-0-CH2CH=CH2 (eq. 1) Pd (0) / THF / 65’ C As can be seen from Table I, ally1 ethers are formed in consistently high yields using this procedure. 4669