Sesquicamphane, Sesquipinane

Following on from Money s important work on the use of a monocyclic precursor for the synthesis of bicyclic and tricyclic sesquiterpenoids, Noyori et al. have now gone one step further and shown that the dibromo-ketone (101) (prepared 

Reagents i, MeCOjH ii, CHjCOj iii, H iv, Bu jAlH v, Me2C=PPh3 vi, POCl3-py 

Reagents i, H2-Pd ii, MeOH-H iii, Bu O iv, HjO jv, EtC0Me-base vi,HC02Me-Me0 vii, LiAlH4 

The two a-santalene derivatives (79) and (80) are constituents of the aerial parts of Ayapana amygdalina. (+)-Epi-c/5-/S-santalol (81) has been identified as a new minor component of East Indian sandalwood oil. Treatment of (+)-a-santalyl acetate (82) with hydrogen chloride followed by dehydrOchlorination with basic alumina produces a mixture of /3-santalyl acetate (83) and the acetate of (81). Last year Christenson and Willis reported the acid-catalysed rearrange- 

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