Two targets from one intermediate: A new rearrangement of vinylcyclopropane into skipped diene is reported. The fundamental understanding of its mechanism obtained by a combined experimental and computational study enabled the development of divergent methodologies toward cyclopentene or skipped diene in a highly selective and controlled manner.
Diastereoselective One-Pot Synthesis of Oxazolines Using Sulfur Ylides and Acyl Imines
作者:Md Shafaat Al Mehedi、Jetze J. Tepe
DOI:10.1021/acs.joc.9b00883
日期:2019.6.7
This work describes an extended version of the Corey–Chaykovsky reaction to access oxazolines using sulfur ylides and stable precursors of acyl imines. The reaction proceeds through a mixture of aziridines and oxazolines, which provides the trans-oxazolines following in situ Heine-type aziridine ring expansion upon treatment with BF3·OEt2. Following the same one-pot procedure, amidine imides react
Diastereoselective Synthesis of Vinylcyclopropanes from Dienes and Sulfur Ylides
作者:Raphaël Robiette、Jacqueline Marchand-Brynaert
DOI:10.1055/s-2008-1032080
日期:——
The reaction of aryl- and vinyl-stabilized sulfonium ylides with electron-poor dienes has been investigated. Clean cyclopropanation to 2-aryl- and 2-vinyl-substituted vinylcyclopropanes, with high regio- and stereocontrol, was observed. This new diastereoselective strategy was applied to formal synthesis of lamoxirene and dictyopterene B.
An efficient two-step no purification protocol for the synthesis of enolizable α-subtituted β,γ-unsaturated aldehydes is reported. The developed strategy involves two steps, epoxidation and Meinwald rearrangement, to result in a formal one-carbon homologation of α,β-unsaturatedaldehydes enabling the insertion of a CHR unit.
One-Carbon Homologation of Knoevenagel Adducts: Enantioselective Access to Benzhydryl Derivatives
作者:Julien Janssens、Madeline De Roose、Alexis Jacquemin、Thomas Vanhosmael、Arnaud Delbrassinne、Laurent Collard、Raphaël Robiette
DOI:10.1021/acs.joc.4c00057
日期:2024.5.17
fragment is reported. The strategy involves a sulfur ylide mediated cyclopropanation followed by the rearrangement of cyclopropanes and enables the synthesis of a series of benzhydryl derivatives. Mechanistic studies reveal that the cyclopropane rearrangement involves a Lewis acid catalyzed ring-opening followed by the 1,2-migration of an aryl group. The possibility of controlling the absolute stereochemistry