Concise stereocontrolled routes to fumagillol, fumagillin, and TNP-470

1,3-Cyclohexadien-1-Als: Synthesis, Reactivity and Bioactivities

In synthetic organic chemistry, there are very useful basic compounds known as building blocks. One of the main reactions wherein they are applied for the synthesis of complex molecules is the Diels-Alder cycloaddition. This reaction is between a diene and a dienophile. Among the most important dienes are the cyclic dienes, as they facilitate the reaction. This review considers the synthesis and reactivity of one of these dienes with special characteristics-it is cyclic and has an electron withdrawing group. This building block has been used for the synthesis of biologically active compounds and is present in natural compounds with interesting properties.

Stereochemical preference of yeast epoxide hydrolase for the O-axial C3 epimers of 1-oxaspiro[2.5]octanes

The 1-oxaspiro[2.5]octane moiety is a common motif in many biologically active spiroepoxide compounds. Stereochemistry plays an important role in the action of these spiroepoxides, since the O-axial C3 epimers are predominantly responsible for biological activity. In view of this, the reactivity of the yeast epoxide hydrolase (YEH) from Rhodotorula glutinis towards both O-axial and O-equatorial C3 epimers of various 1-oxaspiro[2.5]octanes was investigated. O-axial C3 Epimers were hydrolyzed faster than the O-equatorial C3 epimers. The stereochemical preference was greatly dependent on the type of substitution on the cyclohexane ring. The preference of YEH for O-axial C3 epimers, found throughout this study, illustrates the effectiveness of YEH in enzymatic detoxification of spiroepoxides.

A General Method for the α-Acyloxylation of Carbonyl Compounds

[chemical reaction: see text]. A simple, one-pot method for the alpha-acyloxylation of carbonyl compounds that proceeds at room temperature in the presence of both moisture and air has been developed. Treatment of a variety of aldehydes and both cyclic and acyclic ketones with N-methyl-O-benzoylhydroxylamine hydrochloride provides the alpha-functionalized product in 69-92% isolated yield. The transformation is tolerant of a wide range of functional groups and, significantly, is regiospecific in the discrimination of secondary over primary centers in the case of nonsymmetrical substrates.

Total synthesis and antiangiogenic activity of cyclopentane analogues of fumagillol

Novel cyclopentane analogues of fumagillol were synthesized and their endothelial cell proliferation inhibitory activities were evaluated. The cyclopentane-fumagillol derivatives were synthesized from (-)-2,3-O-isopropylidene-D-erythronolactone via stereoselective glycolate Claisen rearrangement and intramolecular ester enolate alkylation as key steps.

A stereoselective asymmetric synthesis of antibiotic (-)-Fumagillol using claisen rearrangement and intramolecular ester enolate alkylation as key steps

(-)-Fumagillol (1), a hydrolysis product of fumagillin, has been synthesized by several group from commercially available 1,2:5,6-di-O-isopropylidene-alpha-D-allofuranose in a highly stereoselective manner. Chiral centers on C5 and C6 came from D-allofuranose and the asymmetric center on C4 was accomplished by 1,3-chirality transfer using the Claisen rearrangement on a chiral allyl alcohol. Chirality, which is necessary on an epoxide consisting of the spiro-ring system, was diastereoselectively constructed by the well-known reaction, intramolecular ester enolate alkylation (IEEA), which showed that this reaction can be applied to the alpha-alkoxy ester system. The epoxide on the side chain was regioselectively introduced by the difference between the number of substituents on the vinyl groups. This accomplishment proved that IEEA can be a useful tool for the synthesis of complex molecules.

Synthesis and biological evaluation of novel fumagillin and ovalicin analogues

A promising approach among the numerous efforts to cure cancer is the interruption of the tumour-induced formation of new blood vessels (angiogenesis). By suppressing angiogenesis with drugs, the tumour can neither grow to a life threatening size, nor metastasize. The natural product fumagillin 1 and the structurally related ovalicin 2 are two of the most potent anti-angiogenic compounds. Here, we report the design and synthesis of novel fumagillin and ovalicin analogues lacking reactive epoxy functionalities, which were thought to be responsible for the severe toxic side-effects observed. We also report a new synthetic approach and the determination of the anti-angiogenic properties of these compounds in endothelial cells.