The first stereoselective total synthesis of the Z-isomer of (6S,7R,9R)-6,7-dihydroxy-9-propylnon-4-eno-9-lactone (original) (raw)
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Stereoselective syntheses and reactions of chiral oxygenated α,β-unsaturated-γ- and δ-lactones
Tetrahedron-asymmetry, 1996
The syntheses of the chiral ~,13-unsaturated lactones (+)-5, (-)-6, (+)-8, (+)-9, and (+)-10 have been efficiently achieved from readily available starting materials. The lactone (+)-5 has been synthesized in 7 steps from (R,R)-dimethyl tartrate (38-43% overall yield). The use of (+)-5 in formal syntheses of natural (+)-asperlin 4 and advanced intermediates for (+)-olguine 2 are also reported. The lactone (-)-6 has been prepared in 5 steps from (R)-malic acid (44-50% overall yield). It can be a useful precursor for the syntheses of branched chain and deoxy nucleoside analogues. The preparation of (-)-6 constitues formal syntheses of natural (+)-eldanolide 53 and the (+)-Geissman-Waiss lactone 54 (an intermediate for the syntheses of a variety of pyrrolizidine alkaloids). The lactones (+)-8, (+)-9 and (+)-10 have been synthesized from 3,4-di-O-acetyI-Lrhamnal 58. The highly diastereoselective transformations of (+)-9 and (+)-10, through sequential conjugate nucleophilic addition and enolate reaction, into densely functionalized chiral y-lactones 12 are also reported.
Stereoselective synthesis of (4S,5R,6S)-4-(5,6-epoxy-6-phenyl)-γ-lactone
Tetrahedron: Asymmetry, 1996
A short (7 steps) and efficient (45% overall yield) synthesis of (4S,SR,6S)-4-(5,6epoxy-6-phenyl)-,/-laetone, a versatile intermediate toward possible HIV-1 protease inhibitors, is described. Two examples of trans-ct-benzylation of the lactonic ring followed by a regioseleetive opening of the epoxide (with thiopropanamide) as well as an opening of the lactone ring with Lvaline (2-methoxy-ethyl)-amide are also given.
Tetrahedron Letters, 2009
We present here the application of Grubbs' 2nd generation catalyst for the ring-closing metathesis of electron-deficient a,b-unsaturated amides and esters leading to the synthesis of enantiopure azepinone and oxepinone derivatives on a carbohydrate glycoside scaffold. The relative stereochemistries of the compounds obtained were corroborated by X-ray crystallography, 1 H NMR or deduced based on previously reported results. These compounds are designed as precursors of new polyhydroxylated heteroannulated sugars with potential biological activity.
New efficient synthesis of (3R,4S)-3-methyl-3-hydroxy-4-phenyl-β-lactam
Tetrahedron: Asymmetry, 1999
A method is described for the chiral synthesis of (3R,4S)-3-methyl-3-hydroxy-4-phenyl-β-lactam, a useful precursor for the semi-synthesis of 2-methyl-taxoids. This protocol follows Seebach's synthetic principle of 'self-regeneration of stereocenters' (SRS) and has been applied to addition reactions of the (2S)-chiral enolates of dioxolan-4-ones, derived from the acetalization of (S)-α-lactic acid and tert-butylaldehyde or pinacolone, to N-trimethylsilylphenyl aldimine.
Recent Developments in γ-Lactone Synthesis
Mini-Reviews in Organic Chemistry, 2009
In recent years, several classes of biologically active molecules containing the -lactone ring, pesticides, plant and fungal growth inhibitors, and antibiotics have been found. Thus the synthesis of substituted dihydrofuran-2(3H) ones is a continuously developing area. Few general synthetic approaches to their stereoselective synthesis with broad structural variety are known. This article reviews the latest developments in the synthesis of -butyrolactones. We focus on the ring-closing steps and pay special attention to how different authors obtain the correspondent 4-hydroxycarbonyl compound; an acyclic synthon for the -lactone ring.
Recent Developments in ?-Lactone Synthesis
Mini Rev Org Chem, 2009
In recent years, several classes of biologically active molecules containing the -lactone ring, pesticides, plant and fungal growth inhibitors, and antibiotics have been found. Thus the synthesis of substituted dihydrofuran-2(3H) ones is a continuously developing area. Few general synthetic approaches to their stereoselective synthesis with broad structural variety are known. This article reviews the latest developments in the synthesis of -butyrolactones. We focus on the ring-closing steps and pay special attention to how different authors obtain the correspondent 4-hydroxycarbonyl compound; an acyclic synthon for the -lactone ring.