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Radikalische Cyclisierung von Dienen, VI. Substratkontrollierte asymmetrische Synthese von (3a S ,6a R )‐(+)‐3,3a,6,6a‐Tetrahydro‐2 H ‐cyclopenta[ b ]furan‐2‐on
Author(s) -
Weinges Klaus,
Schwarz Georg
Publication year - 1993
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.1993199301128
Subject(s) - chemistry , furan , saponification , yield (engineering) , bicyclic molecule , methanesulfonic acid , stereochemistry , stereoselectivity , enone , organic chemistry , catalysis , materials science , metallurgy
Radical‐Type Cyclization of Dienes, VI. – Substrate‐Controlled Asymmetric Synthesis of (3a S ,6a R )‐(+)‐3,3a,6,6a‐Tetrahydro‐2 H ‐cyclopenta[ b ]furan‐2‐one ( R )‐(−)‐Carvone ( 1 ) was converted via straightforward reactions into 10‐hydroxycarvone ( 4 ) which was cyclized to 5 via the mercury‐mediated free‐radical method. Periodate cleavage of 5 yields the bicyclic dione 6 . Regio‐ and stereoselective reduction of 6 with lithium tri( tert ‐butyloxy)hydridoaluminate results in 7 (80% yield). 7 was directly converted into γ‐lactone 8 via Baeyer‐Villiger oxidation. Saponification of 8 to 9 , mesylation of 9 to 10 followed by elimination of methanesulfonic acid yield enantiomerically pure (3a S ,6a R )‐(+)‐3,3a,6,6a‐Tetrahydro‐2 H ‐cyclopenta[ b ]furan‐2‐one ( 11 ). The synthesis can be carried out with readily available, and economical, ( S )‐(+)‐carvone to yield ent ‐ 11 .