A photoredox/nickeldual catalyzed reductive hydrobenzylation of alkynes and benzyl chlorides by employing alkyl amines as a stoichiometric reductant is described. This synergistic protocol proceeds via Markovnikov-selective migratory insertion of an alkyne into nickel hydride, followed by cross-coupling with benzyl chloride, providing facile access to important 1,1-disubstituted olefins. This reaction
B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-Catalyzed Hydrosilylation of Vinylcyclopropanes
作者:Peng-Wei Long、Tao He、Martin Oestreich
DOI:10.1021/acs.orglett.0c02751
日期:2020.9.18
reported. For the majority of VCPs, little or no ring opening of the cyclopropyl unit is observed. Conversely, for VCPs with bulky R groups, such as ortho-substituted aryl rings or branched alkyl residues, ring opening is the exclusive reaction pathway. This finding is explained by the thwarted hydride delivery to a sterically shielded, β-silicon-stabilized cyclopropylcarbinyl cation intermediate.
据报道,强硼路易斯酸B(C 6 F 5)3催化乙烯基环丙烷(VCP)的硅氢化。对于大多数VCP,观察到很少或没有环丙基单元的开环。相反,对于具有庞大R基团的VCP,例如邻位取代的芳基环或支链烷基残基,开环是唯一的反应途径。这一发现可以通过阻止氢化物向空间屏蔽的,β-硅稳定的环丙基羰基阳离子中间物的传递来解释。
Radical 1,5-Chloropentafluorosulfanylation of Unactivated Vinylcyclopropanes and Transformation into α-SF<sub>5</sub> Ketones
作者:Fang-Fang Feng、Jun-An Ma、Dominique Cahard
DOI:10.1021/acs.joc.1c01886
日期:2021.10.1
5-chloropentafluorosulfanylation of vinyl cyclopropanes (VCPs) initiated by Et3B/O2 affords allylic pentafluorosulfanyl/homoallylic chloride products through the ring-strain release of the cyclopropane. The VCP substitution pattern was investigated. The utility of this reaction was illustrated in post-transformation of the C═C bond by ozonolysis, giving access to valuable α-SF5 carbonyl compounds.
Intramolecular Friedel–Crafts alkylation with a silylium-ion-activated cyclopropyl group: formation of tricyclic ring systems from benzyl-substituted vinylcyclopropanes and hydrosilanes
作者:Tao He、Guoqiang Wang、Peng-Wei Long、Sebastian Kemper、Elisabeth Irran、Hendrik F. T. Klare、Martin Oestreich
DOI:10.1039/d0sc05553k
日期:——
alkylation of a silylium-ion-activated cyclopropanering is the rate-determining key step. The reaction mechanism is proposed based on computations and is in agreement with experimental observations. The new reaction leads to an unprecedented silicon-containing 6/6/5-fused ring system. A phenethyl-substituted VCP derivative yields another unknown tricycle having 6/6/6 ring fusion by reacting in a related