Copper-Catalyzed Enantiotopic-Group-Selective Allylation of <i>gem</i>-Diborylalkanes
作者:Minjae Kim、Bohyun Park、Minkyeong Shin、Suyeon Kim、Junghoon Kim、Mu-Hyun Baik、Seung Hwan Cho
DOI:10.1021/jacs.0c11750
日期:2021.1.20
We report a copper-catalyzed enatiotopic-group-selective allylation of gem-diborylalkanes with allyl bromides. The combination of copper(I) bromide and H8-BINOL derived phosphoramidite ligand proved to be the most effective catalytic system to provide various enantioenriched homoallylic boronate esters, containing a boron-substituted stereogenic center that is solely derived from gem-diborylalkanes
Modular, Catalytic Enantioselective Construction of Quaternary Carbon Stereocenters by Sequential Cross-Coupling Reactions
作者:Bowman Potter、Emma K. Edelstein、James P. Morken
DOI:10.1021/acs.orglett.6b01580
日期:2016.7.1
chiral γ,γ-disubstituted allylboronates in the presence of RuPhos ligand occurs with high regioselectivity and enantiospecificity, furnishing nonracemic compounds with quaternary centers. Mechanistic experiments suggest that the reaction occurs by transmetalation with allyl migration, followed by rapid reductive elimination.
A Coupling Approach for the Generation of α,α-Bis(enolate) Equivalents: Regioselective Synthesis of <i>gem</i>-Difunctionalized Ketones
作者:Carmelo E. Iacono、Thomas C. Stephens、Teena S. Rajan、Graham Pattison
DOI:10.1021/jacs.7b12941
日期:2018.2.14
Regioselective α,α-difunctionalization adjacent to a ketone is a significant synthetic challenge. Here, we present a solution to this problem through the transition-metal-free coupling of esters with geminal bis(boron) compounds. This forms an α,α-bis(enolate) equivalent which can be trapped with electrophiles including alkyl halides and fluorinating agents. This presents an efficient, convergent synthetic
Transition-Metal-Free Homologative Cross-Coupling of Aldehydes and Ketones with Geminal Bis(boron) Compounds
作者:Thomas C. Stephens、Graham Pattison
DOI:10.1021/acs.orglett.7b01474
日期:2017.7.7
We report a transition-metal-free coupling of aldehydes and ketones with geminal bis(boron) building blocks which provides the coupled, homologated carbonyl compound upon oxidation. This reaction not only extends an alkyl chain containing a carbonyl group, it also simultaneously introduces a new carbonyl substituent. We demonstrate that enantiopure aldehydes with an enolizable stereogenic center undergo