151867-52-6Relevant articles and documents
Radical-Type Cyclization of Dienes, VI. - Substrate-Controlled Asymmetric Synthesis of (3aS,6aR)-(+)-3,3a,6,6a-Tetrahydro-2H-cyclopentafuran-2-one
Weinges, Klaus,Schwarz, Georg
, p. 811 - 814 (2007/10/02)
(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.Regio- and stereoselective reduction of 6 with lithium tri(tert-butyloxy)hydridoaluminate results in 7 (80percent 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 (3aS,6aR)-(+)-3,3a,6,6a-tetrahydro-2H-cyclopentafuran-2-one (11).The synthesis can be carried out with readily available, and economical, (S)-(+)-carvone to yield ent-11.Key Words: Cyclopentafuran-2-one, (2aS,6aR)-(+)-3,3a,6,6a-tetrahydro-2H- / Radicals / Cyclization / Carvone