反应详情

Phenylacetylene is subject to 1) hydroxymethylation followed by 2) Lindlar reduction to yield cis-cinnamyl alcohol. ##STR6## 3) The cis-cinnamyl alcohol is subjected to the titanium-catalyzed epoxidation process to yield (2S,3R)-epoxy alcohol. ##STR7## 4) This epoxy alcohol is oxidized with RuCl3 and NaIO4, and 5) the reaction product converted to the methyl ester of the epoxide with ethereal diazomethane. 6) This methyl ester of the epoxide is transformed into the desired hydroxyazide by epoxide cleavage using azidotrimethylsilane and a catalytic amount of zinc chloride followed by acid hydrolysis. ##STR8## 7) The hydroxy azide is transformed into azido benzoate and hydrogenated in methanol to produce amino benzoate. 8) The amino benzoate is rearranged to give the product. ##STR9## Modifications in this method have also been described by Denis, J. N. et al., "An Improved Synthesis of the Taxol Side Chain and of RP56976", J. Org. Chem 55, 1957-1959 (1990).