Terpenes, Fatty Acids, and Polyketide Derivatives

In synthetic studies concerning the side chain of tocopherol, Cohen and Saucy [25a] used a chemoenzymatic reaction for the control of the absolute configuration at C-2 and orthoester rearrangement for the control of the absolute configuration 

Hirota, in the total synthesis of quassinoid amaroUde 257 [56], used a non las-sical acidic catalysis with pentachlorophenol. Under these conditions and in the presence of 4 A molecular sieves, the expected ester 259 was obtained in moderate yield. However, large amounts of starting material were recovered. The diastereo- 

MeC(OEt)3, CeCIgOH cat. toluene, Dean-Stark trap 4 A mol sieves 

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