Asymmetric synthesis of optically active 3-substituted .DELTA.-valerolactones using lipase in organic solvents.

Abstract

In organic solvents, lipase AmanoP catalyzed the asymmetric ring opening of glutaric anhydrides bearing -CH2C1, -CH2F and -OCH3groups at position 3 with methanol and 1-butanol to afford the corresponding monoesters in 70-86% e.e. Optically active <5-valerolactones were synthesized from the monoesters in overall yields of 34-62%.The^-configuration was assigned to the monoesters and the lactones by means of a CDanalysis and chemical correlation. This indicates that the lipase preferentially attacked the pro-R carbonyl group of these anhydrides carrying hetero atoms, in keeping with the trend observed for glutaric anhydrides having simple alkyl substituents. 1H); MSm/z(M+): Calcd. forC6H10O3, 130.0630; Found, 130.0634.

8-Endo Cyclization of (Alkoxycarbonyl)methyl Radicals: Radical Ways for Preparation of Eight-Membered-Ring Lactones

“…4-Penten-1-ol, 3-methyl-3-buten-1-ol, and 5-hexen-1-ol were purchased from Aldrich. 4-Methyl-4-penten-1-ol, 4-(trimethylsilyl)-4-penten-1-ol, 1-phenyl-4-penten-1-ol, 2,2-dimethyl-4-penten-1-ol,20c 2,2,4-trimethyl-4-penten-1-ol, 6-hepten-1-ol, 12-tridecen-1-ol, 1,6-heptadien-3-ol, 4,4-dimethyl-1,6-heptadien-3-ol, 1,7-octadien-4-ol, and 2-(2‘-propenyl)-4-penten-1-ol were synthesized according to the literature procedures. 4,4,6-Trimethyl-1,6-heptadien-3-ol ( 21 ), 3-ethenyl-6-hepten-1-ol ( 22 ), and ethyl 6-(2‘-hydroxyethyl)-2,7-octadienoate ( 23 ) were prepared as described below (Scheme ).…”

Stereoselective Anhydride Openings

“…The methodology has also been extended to use of anhydrides bearing substituents other than simple alkyl groups . Their desymmetrization is particularly significant since the products contain additional functional groups at the third position which can be exploited in further derivatization steps (Table ).…”