Patchouli diol

In connection with the synthesis of ( )-patchouli diol (26.1), Yamada and co-workers have examined the cyclization of the aldehyde derived from 26.2 (Scheme 26) (54). This ring closure provides 26.3 in 40% overall yield. Although no information has been provided to indicate whether 26.3 is the only diastereomer produced, the yield suggests that the process occurs with reasonable efficiency. 

A further study on the oxidation of terpenoid compounds by mammalian systems (c/. p. 62) has shown that patchoulol (298) is oxidized by rabbits to give a mixture of diol (299) and hydroxy-acid (300).129 Subsequent oxidative decarboxylation of (300) provided norpatchoulenol (301), the major odour carrier of patchouli oil. It has been suggested that a similar oxidative transformation of patchoulol occurs during the biosynthesis of norpatchoulenol in the plant.129 Cedrol (72) has also been oxidized by rabbits (c/. p. 62) and it is interesting to note that the hydroxylated products are... 

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