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Synthesis of (+)‐13‐Stemarene and (+)‐18‐Deoxystemarin: Expeditious Preparation of the Key 6‐ exo ‐Hydroxybicyclo[2.2.2]octan‐2‐one Ethylene Dithioacetal
Author(s) -
Leonelli Francesca,
Caschera Barbara,
Silvestri Lavinia,
Prastaro Alessandro,
Corso Gaia,
Ceccacci Francesca,
La Bella Angela,
Migneco Luisa Maria,
Bettolo Rinaldo Marini
Publication year - 2008
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200890063
Subject(s) - chemistry , ethylene , benzene , key (lock) , organic chemistry , stereochemistry , catalysis , ecology , biology
An expeditious preparation of the 6‐ exo ‐hydroxybicyclo[2.2.2]octan‐2‐one ethylene dithioacetal 2b , a key intermediate in the synthesis of (+)‐13‐stemarene ( 4 ) and (+)‐18‐deoxystemarin ( 5 ) is described. Compound 2b was obtained as the major product by equilibrating the endo rich mixture of 6‐hydroxybicyclo[2.2.2]octan‐2‐one ethylene dithioacetals 2 with TsOH in benzene at reflux, easily available from the corresponding hydroxy ketones 9 . The model experiments which preceeded the above transformation, not previously described in the literature, are also presented.