In the zone: Pd‐catalyzedoxidativecross‐coupling of N‐tosylhydrazones with allylic alcohols leads to CC bond formation. A palladium–carbene migratory insertion is proposed to play the key role in this transformation. The reaction proceeds with readily available starting materials to afford substituted alkenes in a highly stereoselective manner (see scheme).
Radical Isomerization and Cycloisomerization Initiated by H• Transfer
作者:Gang Li、Jonathan L. Kuo、Arthur Han、Janine M. Abuyuan、Lily C. Young、Jack R. Norton、Joshua H. Palmer
DOI:10.1021/jacs.6b03509
日期:2016.6.22
concentration of an H• donor. Transfer of the H• onto an olefin gives a radical that can either (1) transfer an H• back to the metal, generating an isomerized olefin, or (2) add intramolecularly to a double bond, generating a cyclized radical. Transfer of an H• back to the metal from the cyclized radical results in a cycloisomerization. Both outcomes are favored by the low concentration of the cobalt H• donor,
Regioselective aerobic oxidative Heck reactions with electronically unbiased alkenes: efficient access to α-alkyl vinylarenes
作者:Changwu Zheng、Shannon S. Stahl
DOI:10.1039/c5cc05312a
日期:——
A Pd(TFA)2/2,9-dimethyl-1,10-phenanthroline catalyst enables branched-selective oxidative coupling of arylboronic acids and electronically unbiased alkenes.
Intermolecular Gold-Catalyzed Cycloaddition of Alkynes with Oxoalkenes
作者:Carla Obradors、Antonio M. Echavarren
DOI:10.1002/chem.201300131
日期:2013.3.11
As good as gold: Gold(I) catalyzes a new intermolecular reaction of terminal alkynes with functionalized alkenes that gives 8‐oxabicyclo[3.2.1]oct‐3‐enes by a [2+2+2] cycloaddition process in which two CC bonds and one CO bond are formed (see scheme).
Gold(I)-Catalyzed Cascade Cycloadditions between Allenamides and Carbonyl-Tethered Alkenes: An Enantioselective Approach to Oxa-Bridged Medium-Sized Carbocycles
作者:Hélio Faustino、Isaac Alonso、José L. Mascareñas、Fernando López
DOI:10.1002/anie.201302713
日期:2013.6.17
Gold standard: Allenamides react with aldehydes or ketones having γ, δ, or ε alkenyl groups, upon activation with suitable gold catalysts, to provide oxa‐bridged systems containing seven‐ to nine‐membered carbocycles, in a formal cascadecycloaddition. By using chiral phosphoramidite/gold or bisphosphine/gold catalysts it is possible to obtain the oxa‐bridged seven‐ and eight‐membered rings with good