Using Nazarov Electrocyclization to Stage Chemoselective [1,2]-Migrations: Stereoselective Synthesis of Functionalized Cyclopentenones
作者:David Lebœuf、Jie Huang、Vincent Gandon、Alison J. Frontier
DOI:10.1002/anie.201104870
日期:2011.11.11
Highly functionalizedcyclopentenones have been prepared stereospecifically through a chemoselective copper(II)‐mediated Nazarov/Wagner–Meerwein rearrangement sequence. After the initial 4π electrocyclization, this reaction involves two sequential [1,2]‐migrations depending upon both migratory ability and steric bulk of the substituents at C1 and C5 (see scheme). The proposed mechanism of the reaction
Diastereo- and Enantioselective Synthesis of Structurally Diverse Succinate, Butyrolactone, and Trifluoromethyl Derivatives by Iridium-Catalyzed Hydrogenation of Tetrasubstituted Olefins
作者:Sutthichat Kerdphon、Sudipta Ponra、Jianping Yang、Haibo Wu、Lars Eriksson、Pher G. Andersson
DOI:10.1021/acscatal.9b01508
日期:2019.7.5
A highly efficient iridium N,P-ligand-catalyzed asymmetric hydrogenation of functionalized tetrasubstituted olefins lacking a directing group has been developed. Various structural diverse chiral succinate derivatives were obtained in high yields and excellent enantio- and diastereoselectivities (up to 99% ee) using 0.5–1.0 mol % catalyst loadings. This stereoselective reaction is applicable for the
A convenient route to α,β-unsaturated methyl ketones application to retinal analogue synthesis
作者:Allan A. Croteau、John Termini
DOI:10.1016/s0040-4039(00)81960-7
日期:1983.1
Deprotonated ketimines , add to aldehydes and ketones to provide tri- and tetra-substituted α,β-unsaturated methylketones , with substantial percentage of -geometry which are not readily accessible by other methods.