Eremophilone synthesis

A second stereoselective total synthesis of ( )-eremophilone (243) has been accomplished using 7-epinootkatone (242) as intermediate.109 The latter compound was synthesized from (—)-/3-pinene (241) by modification of the published procedure"0 and subsequently converted into eremophilone (243) by the series of functional-group transformations shown in Scheme 30. A mycotoxin isolated from Penicillium roqueforti has been assigned the highly oxygenated eremophilane structure (244) on the basis of chemical and spectroscopic evidence."1 The structure and... 

Allylic epoxides seem to behave normally. Stereospecific hydride migrations were observed in the McMurry et al. synthesis of eremophilone. Treatment of the isomeric epoxides (268) and (270) under standard conditions resulted in the exclusive formation of the rearranged ketones, as illustrated in equations (114) and (115). 

Robinson annelation. Robinson annelation of substituted cyclohexanones with the reagent offers an entry into eremophilone-type sesquiterpenes. Thus the total synthesis of ( )-nootkatone (2) has been achieved by the annelation of (1) with frans-3-pentene-2-one in the presence of sodium hydride.3 In this case only one isomer was isolated. However, Coates and Shaw4 noted that the steric outcome of... 

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