34495-67-5Relevant academic research and scientific papers
Asymmetric total synthesis of an a-ring precursor to hormonally active 1α,25-dihydroxyvitamin D3
Posner,Kinter
, p. 3967 - 3969 (1990)
A new sulfinyl orthoester has been designed and used effectively in one-flask syntheses of dienoate esters from allylic alcohols; this new method as well as a highly stereocontrolled [2 + 4]-cycloaddition are applied to synthesis of 1α,25-dihydroxyvitamin D3.
N-Alkenyl Nitrone Dipolar Cycloaddition Routes to Piperidines and Indolizines. Part 6. Allylic Stereocontrol in the Intramolecular Cyclisation of Monosubstituted Nitrones
Collins, Ian,Nadin, Alan,Holmes, Andrew B.,Long, Martin E.,Man, Jocelyn,Baker, Raymond
, p. 2205 - 2216 (2007/10/02)
The intarmolecular, thermal dipolar cycloadditions of the (Z)-N-alk-4-enyl nitrones 18-21, 34 and 36 bearing a single, allylic substituent were investigated.Certain alkoxy substituted nitrones 18-21 showed a remarkable preference for the formation of axially substituted isoxazolidines 22a-24a, whereas the propyl and trifluoromethyl substituted nitrones 35 and 34 gave the equatorially substituted cycloadducts 37 and 36a respectively, consistent with the involvement of 'chair-like' transition states 38.
One-Flask, Regiospecific Conversions of Allylic Alcohols into Two-Carbon-Extended, Conjugated Dienoate Esters. Use of a New Sulfinyl Orthoester
Posner, Gary H.,Crouch, R. David,Kinter, Chris M.,Carry, Jean-Christophe
, p. 6981 - 6987 (2007/10/02)
Sixteen differently substituted primary and secondary allylic alcohols are shown to react with sulfinyl orthoacetate 1 at 100 deg C sequentially via a sigmatropic rearrangement and then a β-elimination of benzenesulfenic acid to form conjugated dienoate esters 5-13 in 45-95percent yields.This one-flask, intramolecular carbon-carbon bond-forming process represents a simple and convenient method for regiospecific γ-attachment of a two-carbon (ethoxycarbonyl)methylene unit via the synthetic equivalent of an SN2' process.Two examples are given in which rationally designed dienoates 20 and 24, prepared via this one-flask process and carrying a pendant alkene unit, undergo intramolecular 2+4 cycloaddition producing bicyclic cyclohexenes 21 and 25.
