Process for preparing taxol side chain using heterogeneous trifunctional catalyst

The present invention relates to an improved process for the preparation of taxol side chain that comprises the following steps: (a) Synthesis of (2R,3S)-2,3-dihydroxy-3-phenylpropionate with greater than 99% enantioselectivity and devoid of osmium even in the crude in a single pot using recyclable multifunctional catalysts of the formula IE-IE-PdOsW, in which IE is a ion-exchanger comprising LDH, quaternary ammonium salt anchored on silica, clay, alumina, magnesia or resin (b) conversion of the diol thus obtained without further crystallization into bromoacetate using standard protocol, (c) reaction of bromoacetate with NaN in DMF followed by deacetylation with NaOAc in MeOH affords azido alcohol (d) benzoylation followed by hydrogenation of azido alcohol gave the (2R,3S)-(N-)-benzoyl-3-phenylisoserine methyl ester in 67% overall yield. The present invention relates to an improved process for the preparation of taxol side chain by synthesizing (2R,3S)-2,3-dihydroxy-3-phenylpropionate with greater than 99% enantioselectivity and devoid of osmium even in crude form in a single pot using a recyclable multifunctional catalysts, conversion of diol obtained without further crystallization into bromoacetate, reaction of bromoacetate with NaNin organic solvent followed by deacetylation with to obtain azido alcohol, benzoylation followed by hydrogenation of azido alcohol to obtain the (2R,3S)-(N-)-benzoyl-3-phenylisoserine methyl ester in 67% yield.