Yvan Guindon

The synthesis of a leukotriene with SRS-like activity

Abstract The synthesis and biological characteristics of an SRS-like leukotriene are described.

The stereospecific synthesis of leukotriene A4 (LTA4), 5-epi-LTA4, 6-epi-LTA4 and 5-epi,6-epi-LTA4

The stereospecific syntheses of the four isomers of 6-formyl-5,6-epoxy hexanoic acid methyl ester 8, 15, 23 and 30 from Z-deoxy-D-ribose have allowed the preparation of methyl esters of LTA4, 1, and its three unnatural isomers.

Stereospecific synthesis of leukotriene B4 (LTB4)

Abstract A stereospecific and chirally economical synthesis of LTB 4 starting from 2-deoxy-D-ribose is reported as part of a comprehensive and efficient approach to the Leukotrienes (A, B, C, D, E). The process includes a novel approach to chiral dienic synthons.

Cleavage of carbonoxygen bonds. Dimethylboron bromide. A new reagent for ether cleavage

Abstract A general and efficient procedure for the cleavage of aliphatic, aromatic and cyclic ethers by the use of dimethylboron bromide is described.

Stereoselective reduction of acyclic α-bromo esters

Abstract Radical-based reduction of β-methoxy- or β-fluoro-α-bromo esters could be achieved with good stereoselection at low temperatures. A systematic evaluation of this reaction is presented and possible transition state models are discussed.

Stereoelectronic effects in the ring cleavage of methyl glycopyranosides using dimethylboron bromide

Abstract Treatment of methyl D-glycopyranosides with dimethylboron bromide followed by a nucleophile gives acyclic products resulting from selective cleavage of the ring carbon-oxygen bond. The results are rationalized based on stereoelectronic considerations.

A C-glycoside route to leukotrienes

Abstract The stereospecific syntheses of three isomers of 7-hydroxy-5,6-epoxy heptanoic acid methyl ester, 7 , 12b and 19 , have been achieved via a C -glycoside route.

LARGE SCALE PREPARATION OF (2S,3S)-N-BOC-3-AMINO-1,2-EPOXY-4-PHENYLBUTANE : A KEY BUILDING BLOCK FOR HIV-PROTEASE INHIBITORS

Abstract (2S,3S)-N-Boc-3-amino-1,2-epoxy-4-phenylbutane is prepared in four steps from commercially available N,N-dibenzyl-L-phenylalaninol. The synthesis is amenable to the preparation of kilogram quantities of enantiomerically pure material.

The effect of polar substituents on the conformation and stereochemistry of enolate radicals

Abstract ESR measurements and AM1 calculations show that ester substituted radicals 2 and 6 prefer conformation A as a result of allylic strain effects. But dipolar repulsion between substituents X and CO2Et In 2 and 6 has a pronounced effect on the conformation and the stereoselectivity of radicals 2 and 6.

Stereoselective rardical-mediated reduction and alkylation of α-halo esters

Abstract Radical-mediated reduction and alkylation of β-alkoxy-α-halo esters could be achieved with good stereoselection at low temperature.