Synthesis of Vinyl Boronates from Aldehydes by a Practical Boron–Wittig Reaction
作者:John R. Coombs、Liang Zhang、James P. Morken
DOI:10.1021/acs.orglett.5b00480
日期:2015.4.3
A highly stereoselectiveboron-Wittigreaction between stable and readily accessible 1,1-bis(pinacolboronates) and aldehydes furnishes a variety of synthetically useful di- and trisubstituted vinyl boronate esters.
C–O Functionalization of α-Oxyboronates: A Deoxygenative <i>gem</i>-Diborylation and <i>gem</i>-Silylborylation of Aldehydes and Ketones
作者:Lu Wang、Tao Zhang、Wei Sun、Zeyu He、Chungu Xia、Yu Lan、Chao Liu
DOI:10.1021/jacs.7b02518
日期:2017.4.12
the success of this transformation is the base-promoted C-O bond borylation or silylation of the generated α-oxyboronates. Experimental and theoretical studies exhibit that the C-O bond functionalization proceeds via an intramolecular five-membered transition-state (9-ts) boryl migration followed by a 1,2-metalate rearrangement with OBpin as a leavinggroup. The transformation occurs with an inversion
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
place at α-, β-, and γ-C–H bonds, giving polyborylated products including di-, tri-, tetra-, and even pentaborylalkanes. α-C–H borylation was generally found to be the preferred reaction of primary alkylboronic acid derivatives, whereas β- or γ-borylation also occurred if β- or γ-C–H bonds were located on the methyl group.
Diborylalkyllithium Salts Trigger Regioselective Ring Opening of Vinyl Aziridines
作者:Oriol Salvado、Riccardo Gava、Elena Fernández
DOI:10.1021/acs.orglett.9b03672
日期:2019.11.15
nucleophilic attack on vinyl aziridines with controlled regioselectivity. Preferred SN2 diborylalkylation ringopening reaction on the less sterically hindered position is observed with 1-tosyl-2-vinylaziridine, whereas exclusive SN2′ nucleophilic attack occurs on 2-methyl-1-tosyl-2-vinylaziridine. Cyclic vinyl aziridines interact through a third venue, via SN2 diborylalkylation ringopening reaction on the allylic
经LiTMP处理的gem -Diborylalkanes生成α-diborylalkane锂碱,该碱对区域的乙烯基氮丙啶进行亲核攻击,并具有可控的区域选择性。优选的小号Ñ就少的空间位阻的位置2 diborylalkylation开环反应与1-甲苯磺酰基-2- vinylaziridine观察到的,而排斥小号Ñ上2-甲基-1-对甲苯磺酰-2- vinylaziridine发生2'的亲核攻击。环状乙烯基氮丙啶经由烯丙基位置上的S N 2二硼烷基烷基化开环反应通过第三位点相互作用。在完全立体化学控制下形成均烯丙基二硼酸酯。