Phosphine‐Catalyzed Activation of Alkylidenecyclopropanes: Rearrangement to Form Polysubstituted Furans and Dienones
作者:Xin He、Yuhai Tang、Yongzhuang Wang、Jian‐Bo Chen、Silong Xu、Jianwei Dou、Yang Li
DOI:10.1002/anie.201903320
日期:2019.7.29
We report a phosphine‐catalyzed ring opening of electron‐deficient alkylidenecyclopropanes (ACPs) to generate allylic phosphonium zwitterions that resemble the well‐studied phosphine‐allene adducts but exhibit distinct properties. The potent reactivity of these intermediates has been demonstrated in three types of substrate‐controlled phosphine‐catalyzed rearrangements of alkylidenecyclopropylketones
Photocatalytic Metal Hydride Hydrogen Atom Transfer Mediated Allene Functionalization by Cobalt and Titanium Dual Catalysis
作者:Huaipu Yan、Qian Liao、Yuqing Chen、Gagik G. Gurzadyan、Binghui Lu、Chao Wu、Lei Shi
DOI:10.1002/anie.202302483
日期:2023.6.12
Reported is on the photo Co metal hydride hydrogen atom transfer (MHAT) reaction for chemoselective allene functionalization by using Co-porphines as catalysts and the Hantzsch ester as an H atom and electron donor. The merger of Co MHAT and Ti catalysis under photoredox conditions enabled successful carbonyl allylation, providing access to valuable β-functionalized homoallylic alcohols with exceptional
报道了通过使用 Co-卟啉作为催化剂和 Hantzsch 酯作为 H 原子和电子供体,用于化学选择性丙二烯功能化的照片 Co 金属氢化物氢原子转移 (MHAT) 反应。在光氧化还原条件下,Co MHAT 和 Ti 催化的结合使羰基烯丙基化反应成功,为获得具有特殊区域选择性和非对映选择性的有价值的 β-官能化高烯丙醇提供了途径。
Selective Hydrosilylation and Hydroboration of Allenes Catalyzed by Cobalt‐Pincer Complexes
作者:Dariusz Lewandowski、Grzegorz Hreczycho
DOI:10.1002/adsc.202400309
日期:——
regioselectivity and stereoselectivity in the hydroelementation of terminalallenes presents a formidable challenge. Despite the existence of various catalytic methods for their functionalization, this entire class of reactions remains significantly underdeveloped and demands extensive research. Here, we report a method for the hydroelementation of allenes using inexpensive PN5P pincer cobalt complexes built on
Palladium-catalyzed cross-coupling reaction of bis(iodozincio)methane with iodoarenes carrying various functionalities such as ester, boryl, cyano, and halo groups proceeded chemoselectively to give the corresponding arenylmethylzinc species efficiently. The moderate reactivity of the gem-dizinc reagent imparted functional group tolerance to the process. The transformations from iodoheteroarenes were also performed; in the case of iodopyridine derivatives, the nickel-catalyzed reaction gave the corresponding organozinc species efficiently. The obtained arenylmethylzinc species underwent the copper-mediated coupling reaction with a range of organic halides.
BROWN H. C.; LIOTTA R.; KRAMER G. W., J. AMER. CHEM. SOC., 1979, 101, NO 11, 2966-2970