Selective Deprotection of Acetals with Me3SiCH2MgCl. Peterson-Type Olefination of Acetals
摘要:
By employing the chelation strategy, treatment of an acetal of a contiguous diol with Me3SiCH2MgCl liberates the corresponding diol regioselectively. In addition, acetals of different structural variety are transformed upon treatment with Me2SiCH2MgCl and ZnI2 into the corresponding olefination products in good yield.
Hydroalkylation of Unactivated Olefins via Visible-Light-Driven Dual Hydrogen Atom Transfer Catalysis
作者:Guangyue Lei、Meichen Xu、Rui Chang、Ignacio Funes-Ardoiz、Juntao Ye
DOI:10.1021/jacs.1c05852
日期:2021.7.28
hydroalkylation of olefins enabled by hydrogen atom transfer (HAT) catalysis represents a straightforward means to access C(sp3)-rich molecules from abundant feedstock chemicals without the need for prefunctionalization. While Giese-type hydroalkylation of activated olefins initiated by HAT of hydridic carbon–hydrogen bonds is well-precedented, hydroalkylation of unactivated olefins in a similar fashion
通过氢原子转移 (HAT) 催化实现的烯烃自由基加氢烷基化代表了一种直接获得 C( sp 3)-丰富的分子来自丰富的原料化学品,无需预官能化。虽然由氢化碳-氢键的 HAT 引发的活性烯烃的 Giese 型加氢烷基化是有先例的,但未活化烯烃以类似方式的加氢烷基化仍然难以捉摸,主要是由于缺乏克服固有极性不匹配的通用方法。设想。在这里,我们报告了使用可见光驱动的双 HAT 催化来实现这一目标,其中催化量的胺硼烷和原位生成的硫醇分别用作氢原子提取物和供体。该反应是完全原子经济的,具有广泛的范围。
A Photoirradiative Phase-Vanishing Method: Efficient Generation of HBr from Alkanes and Molecular Bromine and Its Use for Subsequent Radical Addition to Terminal Alkenes
phase-vanishing (PV) system comprised of an alkane, perfluorohexanes, and bromine was successfully combined by photoirradiation to efficiently generate hydrogenbromide, which underwent radicaladdition with 1-alkenes in the hydrocarbon layer to afford terminal bromides in high yields.
An efficient RhII -catalyzed synthesis of functionalized α-vinyl aldehydes with high E/Z stereoselectivity was developed. The reaction mediates the cyclopropanation of enaminones with vinyl carbenoids that are generated from cyclopropenes in situ to give the aminocyclopropane intermediates. Selective C-C bond cleavage of the cyclopropane intermediates leads to formation of α-vinyl aldehyde derivatives
A mild rhodium catalytic system has been developed to synthesize vinylcyclopropa[b]indolines through cyclopropanation of indoles with vinyl carbenoids generated from ringopening of cyclopropenes in situ. By employing a Rh-migration strategy, the products can be obtained with good to excellent E:Z ratios (≤99:1) and complete diastereoselectivity (≤99:1). This method is easy, has a low catalyst loading
已开发出一种温和的铑催化体系,通过将吲哚与原位环丙烯开环生成的乙烯基类胡萝卜素进行环丙烷化,来合成乙烯基环丙烷[ b ]二氢吲哚。通过采用Rh迁移策略,可以获得具有良好或优异的E:Z比(≤99:1)和完全非对映选择性(≤99:1)的产物。该方法容易,催化剂负载低并且适用于广泛的功能。
Dehydration of alcohols catalyzed by copper(II) sulfate adsorbed on silica gel
Copper(II) sulfate adsorbed on silica gel efficientlydehydrated secondary and tertiary alcohols under mild conditions to give olefins. The rate of dehydration of tertiary alcohols is much faster than that of secondary alcohols.