Stereoselective synthesis of α-alkylidene- and substituted alkylidene-γ-lactones (original) (raw)

An efficient synthesis of -(alkylidene)-5, 5-dimethyl- -lactones

2009

Alkylidene substituted)-5,5-dimethyl-δ-lactones have been synthesized in two steps. The stable phosphorane carboethoxymethyledene (α-prenyl)-triphenylphosphorane is condensed with different carbonyl compounds to afford α,β-unsaturated esters which are cyclised using PPA to give title compounds.

A total stereospecific route to α-alkylidene-γ-lactams

Tetrahedron, 2001

AbstractÐA new ef®cient g-lactams 4 synthesis was achieved by two successive reactions: alkylation of nitroalkane anions with dimethyl a-(bromomethyl) fumarate 1 leading to the formation of (E)-1-alkyl-2,3-dimethoxycarbonyl butadienes 3a,b resulting of tandem alkylation± elimination (dehydronitration) processes, followed by an intramolecular cyclization on addition of primary amine. q 2001 Published by Elsevier Science Ltd.

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.

Diastereoselective Synthesis of Functionalized δ‐Lactones

Synthetic Communications, 2004

a b s t r a c t This paper describes a convenient synthesis of disubstituted functionalized d-lactams based on Michael addition of primary amines to dimethyl-E-2-alkylidene glutarates 2 followed by an intramolecular cyclisation.

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.

Synthesis and antitumor activity of α-alkyliden-γ- lactones

International Journal of Pharmaceutical Research, 2018

The α-methylene-γ-butyrolactone skeleton is part of many natural products with remarkable biological properties. C75, a fatty acid synthase (FAS) inhibitor, is a synthetic α-methylene-γ-butyrolactone which is cytotoxic for different cell lines in vitro and in vivo against human cancer xenografts. We synthesized a panel of C75 derivatives through modifications of the α-methylene moiety at the C-β/C- carbons of the γ-butyrolactone skeleton and tested their effects on different cancer models. The in vitro effects of the compounds on pancreatic, colon and breast cancer cell viability (PANC-1, HTC-116, Lovo, MCF-7, MDA-231-MB) were evaluated. Two compounds showed significant cytotoxicity. The structures of all synthesized compounds obtained were identified on the basis of their spectral data (IR, MS, NMR).

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.