109985-76-4Relevant academic research and scientific papers
Stereochemistry of the Intermolecular and Intramolecular Conjugate Additions of Amines and Anions to Chiral (E)- and (Z)-Vinyl Sulfoxides. Total Syntheses of (R)-(+)-Carnegine and (+)- and (-)-Sedamine
Pyne, Stephen G.,Bloem, Peter,Chapman, Sandra L.,Dixon, Christine E.,Griffith, Renate
, p. 1086 - 1093 (2007/10/02)
The intramolecular addition of incipient amine anions to chiral (E)- and (Z)-vinyl sulfoxides occurs in the same diastereofacial sense, giving chiral isoquinoline and piperidine derivatives that differ in relative stereochemistry at C-2.In contrast, the conjugate addition reactions of (E)- and (Z)-β-styryl p-tolyl sulfoxide wih benzylamine and LiCH(CO2Et)2 are diastereoconvergent processes.The same major diastereomeric product is obtained in each case.We have attempted to rationalize the stereochemical outcome of the addition of nucleophiles to chiral vinyl sulfoxides according to the type of nucleophilic reagent employed (either chelating/hydrogen bonding or nonchelating) and from a consideration of possible transition states.
Diastereoselective Additions of (R)-(+)-Methyl p-Tolyl Sulfoxide Anion to Imines. Asymmetric Synthesis of (R)-(+)-Tetrahydropalmatine
Pyne, Stephen G.,Dikic, Branko
, p. 1932 - 1936 (2007/10/02)
The addition of the lithium carbanion of methyl phenyl sulfoxide and (R)-(+)-methyl p-tolyl sulfoxide to imines having at least one aryl substituent, under kinetically controlled conditions, gives β-amino sulfoxides with good to modest diastereoselection.Under equilibrium controlled condition poor product diastereoselection results.The addition of these anions to 3,4-dihydro-6,7-dimethoxyisoquinoline is unique in that the most favorable product diastereoselection (92:8) is observed under equilibrium controlled conditions.Deuteration experiments suggest that equilibration occurs via a β-amino α-lithio sulfinyl carbanion through a retro-Michael addition then Michael addition reaction sequence.This methodology allows for the construction of (R)-(+)-tetrahydropalmatine in four efficient synthetic steps.
Asymmetric Intramolecular Conjugate Addition of Amines to Chiral Vinyl Sulphoxides. Total Synthesis of (R)-(+)-Carnegine
Pyne, Stephen G.,Chapman, Sandra L.
, p. 1688 - 1689 (2007/10/02)
The (E)- and (Z)-vinyl sulphoxides (3) and (4) upon treatment with base, undergo cyclization to give chiral isoquinolines one of which was converted into (R)-(+)-carnegine.
