1726-14-3Relevant articles and documents
Lewis acid-catalyzed ring-opening reactions of methylenecyclopropanes with alcoholic or acidic nucleophiles
Shi, Min,Xu, Bo
, p. 2145 - 2148 (2002)
(matrix presented) Nu-H can be alcohols, thiols, phenols, carboxylic acids yield: 60%-100%. Methylenecyclopropanes can react with various nucleophiles such as alcohols, phenols, carboxylic acids, and thiols to give the corresponding homoallylic esters or
Early main group metal catalysis: How important is the metal?
Harder, Sjoerd,Penafiel, Johanne,Maron, Laurent
, p. 201 - 206 (2015)
Organocalcium compounds have been reported as efficient catalysts for various alkene transformations. In contrast to transition metal catalysis, the alkenes are not activated by metal-alkene orbital interactions. Instead it is proposed that alkene activation proceeds through an electrostatic interaction with a Lewis acidic Ca2+. The role of the metal was evaluated by a study using the metal-free catalysts: [Ph2N-Me4N+] and [Ph3C-][Me4N- ]. These "naked" amides and carbanions can act as catalysts in the conversion of activated double bonds (C=O and C=N) in the hydroamination of Ar-N=C=O and R-N=C=N=R (R=alkyl) by Ph2NH. For the intramolecular hydroamination of unactivated C=C bonds in H2C=CHCH2CPh2CH2NH2 the presence of a metal cation is crucial. A new type of hybrid catalyst consisting of a strong organic Schwesinger base and a simple metal salt can act as catalyst for the intramolecular alkene hydroamination. The influence of the cation in catalysis is further evaluated by a DFT study.
Bromomethyl Silicate: A Robust Methylene Transfer Reagent for Radical-Polar Crossover Cyclopropanation of Alkenes
Luo, Wenping,Fang, Yewen,Zhang, Li,Xu, Tianhang,Liu, Yongjun,Li, Yan,Jin, Xiaoping,Bao, Jiakan,Wu, Xiaodong,Zhang, Zongyong
, p. 1778 - 1781 (2020/03/11)
A general protocol for visible-light-induced cyclopropanation of alkenes was developed with bromomethyl silicate as a methylene transfer reagent, offering a robust tool for accessing highly valuable cyclopropanes. In addition to α-aryl or methyl-substituted Michael acceptors and styrene derivatives, the unactivated 1,1-dialkyl ethylenes were also shown to be viable substrates. Apart from realizing the cyclopropanation of terminal alkenes, the methyl transfer reaction has been further demonstrated to be amenable to the internal olefins. The photocatalytic cyclopropanation of 1,3-bis(1-arylethenyl)benzenes was also achieved, giving polycyclopropane derivatives in excellent yields. With late-stage cyclopropanation as the key strategy, the synthetic utility of this transformation was also demonstrated by the total synthesis of LG100268.
Conversion of Carbonyl Compounds to Olefins via Enolate Intermediate
Cao, Zhi-Chao,Xu, Pei-Lin,Luo, Qin-Yu,Li, Xiao-Lei,Yu, Da-Gang,Fang, Huayi,Shi, Zhang-Jie
supporting information, p. 781 - 785 (2019/06/24)
A general and efficient protocol to synthesize substituted olefins from carbonyl compounds via nickel catalyzed C—O activation of enolates was developed. Besides ketones, aldehydes were also suitable substrates for the presented catalytic system to produce di- or tri- substituted olefins. It is worth noting that this approach exhibited good tolerance to highly reactive tertiary alcohols, which could not survive in other reported routes for converting carbonyl compounds to olefins. This method also showed good regio- and stereo-selectivity for olefin products. Preliminary mechanistic studies indicated that the reaction was accomplished through nickel catalyzed C—O activation of enolates, thus offering helpful contribution to current enol chemistry.
Palladium-Catalyzed C?H Alkenylation of Arenes with Alkynes: Stereoselective Synthesis of Vinyl Chlorides via a 1,4-Chlorine Migration
Li, Zhen,Duan, Wei-Liang
supporting information, p. 16041 - 16045 (2018/11/23)
A directing group-free, ligand-promoted palladium-catalyzed C?H arylation of internal alkynes with simple arenes was developed. Alkenyl chlorides resulting from a 1,4-chlorine migration or trisubstituted alkenes were produced in moderate to good yields depending on the type of alkyne.
