131700-28-2Relevant articles and documents
Enantioselective Synthesis of 2-Methyl-2-hydroxy-γ-butyrolactone and Its Application in the Asymmetric Synthesis of Frontalin and Mevalonolactone
Davis, Franklin A.,Reddy, G. Venkat,Chen, Bang-Chi,Kumar, Anil,Haque, M. Serajul
, p. 6148 - 6153 (1995)
The asymmetric hydroxylation of the enolates of fully substituted acyclic ester 8 and lactone 10 with (camphorylsulfonyl)oxaziridines 1a - c was studied.The stereoselectivities of the tertiary α-hydroxy carbonyl products were highly dependent on the enolate structure, the oxidizing reagents, and the reaction conditions.While high diastereoselectivity (up to 94percent) was obtained for enolates of fully substituted menthol ester 8 with substoichiometric amounts of oxaziridine 1a, the yields were unsatisfactory.On the other hand, the enantioselective α-hydroxylation of the sodium enolate of 2-methyl-γ-butyrolactone (10) with oxaziridine (1c) afforded α-hydroxy lactone 11a in 70percent yield and 84percent ee.The enantiomeric excess was improved to >93percent ee by crystallization of the corresponding benzoyl ester 11c.The utility of both enantiomers of 11c were demonstrated in the formal asymmetric syntheses of the pheromone, (1S,5R)-(-)-frontalin (13) and in the asymmetric synthesis of (R)-(-)-mevalonolactone (20).
Pigments of Fungi. LIX - Synthesis of (1S,3S)- and (1R,3R)-austrocortilutein and (1S,3S)-austrocortirubin from citramalic acid
Gill, Melvyn,Harte, Michael F.,Ten, Abilio
, p. 245 - 256 (2007/10/03)
The naturally occurring tetrahydroanthraquinone (1S,3S)-austrocortilutein (1) is synthesized for the first time in enantiomerically pure form by Diels-Alder cycloaddition between the functionalized butadiene derivative (8) and the chiral 1,3-dihydroxy-1,2,3,4-tetrahydro-5,8-naphthoquinone (9), the latter being derived from (R)-citramalic acid (3). The natural products (1S,3S)-austrocortirubin (2) and (1R,3R)-austrocortilutein (5) were also prepared for the first time by using the same strategy. CSIRO 2000.