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The chemistry of thujone. IX . Thujone as a chiral synthon for the synthesis of optically active steroid analogues. The vinylpicoline route
Author(s) -
Kutney James P.,
Grice Peter,
Piotrowska Krystyna,
Rettig Steven J.,
Szykula Jerzy,
Trotter James,
Van Chu Loc
Publication year - 1983
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.19830660621
Subject(s) - chemistry , synthon , enone , steroid , cyclohexenone , absolute configuration , chirality (physics) , acetal , stereochemistry , ring (chemistry) , kinetic resolution , optically active , derivative (finance) , diketone , pyridine , aldol reaction , organic chemistry , catalysis , enantioselective synthesis , biochemistry , chiral symmetry breaking , physics , quantum mechanics , hormone , nambu–jona lasinio model , quark , financial economics , economics
The thujone‐derived enone 1 , upon base‐catalyzed reaction with 2‐methyl‐6‐vinylpyridine is converted to the pyridine analogue 5 (Scheme 1) . Catalytic reduction of the latter to 6 generates two new centers of chirality which eventually become C(8) and C(14) in the ultimate synthetic steroid analogue 12 . An X‐ray analysis of 6 establishes the structure and absolute configuration so as to determine its suitability in subsequent synthetic studies. The acetal derivative 7 , via Birch reduction, hydrolysis, and internal aldol cyclization, is converted into the cyclohexenone analogue 10 (Scheme 2) . This ‘one‐pot’ process affords an efficient conversion of the pyridine ring into a cyclohexenone system required for A‐ring construction of the steroid skeleton. Finally, conversion of 10 , via the unsaturated diketone 11 , provides the chiral steroid analogue 12 .