Diastereoselective Nucleophilic Addition Research Articles

Asymmetric synthesis using chiral acetals: Highly diastereoselective nucleophilic addition of Grignard reagents to chiral 1-oxo-.BETA.-tetralone 1-acetals.

Asymmetric synthesis using chiral acetals: Highly diastereoselective nucleophilic addition of Grignard reagents to chiral 1-oxo-.BETA.-tetralone 1-acetals.

Doubly diastereoselective nucleophilic additions to a bicyclic β,γ-unsaturated ketone possessing a conformationally mobile double bond

(7 R *)-7-Methyl-7-vinylbicyclo [3.2.0] hept-2-en-6-one was condensed with several chiral cyclopentenyllithium reagents for the purpose of assaying the diastereoselectivity of this coupling. Due to ring strain, the alkoxides that are formed spontaneously undergo anionic oxy-Cope rearrangement. The initial diastereoselectivity is thereby incorporated into additional stereogenic centers. The mechanistic details of the two steps are discussed. Although the resultant diastereoselectivity is low, it is shown that polycyclic networks with as many as nine asymmetric carbons can be cleanly elaborated in very few steps.

ChemInform Abstract: Diastereoselective Nucleophilic Additions to a Chiral Monoacetal of Glyoxal.

ChemInform Abstract: Diastereoselective Nucleophilic Additions to a Chiral Monoacetal of Glyoxal.

ChemInform Abstract: Diastereoselective Nucleophilic Addition to Chiral Open‐Chain α‐Ketoacetals: Synthesis of (R)‐ and (S)‐mevalolactone.

AbstractAus den Acetalen (I) erhält man mit dem (‐)‐(2S,3S)‐Butandiol (II) durch Umacetalisierung die cyclisuchen Acetale (III), die nach Oxidation zu den Carbonylverbindungen (IV) mit den Organo‐Meta11verbindungen (V) zu den Addukten (VI) und (VII) führen.

Diastereo- and enantioselective preparation of β-alkylhomoallylic alcohols : Synthesis of serricornin and corynomycolic acid

A new and efficient method for the preparation of four possible stereoisomers of β-alkylhomoallylic alcohols 1 has been developed which is based on the diastereoselective addition of nucleophiles to optically active α-alkyl-β-trimethylsilyl-β,γ-unsaturated carbonyl compounds. The utility of this reaction is demonstrated by the synthesis of naturally occurring serricornin and corynomycolic acid.

Diastereoselective nucleophilic addition to chiral open-chain α-ketoacetals: Synthesis of (R)- and (S)-mevalolactone

Highly stereoselective addition of Grignard reagents to chiral open-chain α,-ketoacetals ( 3a , 3b ) has been attained. Application of the reaction to syntheses of the key intermediates ( 6 , 8 ) for (R)- and (S)-mevalolactone is also described.

A SIMPLE STEREOCONTROLLED SYNTHESES OF OPTICALLY ACTIVE DEOXYSUGARS l-RHODINOSE AND d-AMICETOSE

Abstract Facile stereoselective syntheses of 2,3,6-trideoxysugars, l-rhodinose and d-amicetose, were achieved from highly diastereoselective nucleophilic addition of methyl group to (S)-2-benzyloxy-5-hexenal, which was easily obtained from optically pure (S)-glycidyl sulfide.

Highly stereoselective approach to chiral building block possessing three contiguous asymmetric centers. Preparation of four possible diastereomers of β,β′-dimethyl-bis-homoallylic alcohol derivative

All four diastereomere of chiral alcohol 2 with three contiguous chiral centers were stereoselectively prepared via diastereoselective addition of nucleophiles (crotyl metal or H -) to α-methyl-β,γ-unsaturated carbonyl compounds 1 .