An “Anti-Baldwin” 3-Exo-Dig Cyclization: Preparation of Vinylidene Cyclopropanes from Electron-Poor Alkenes
摘要:
Stabilized carbanions undergo an uncommon 3-exodig cyclization onto propargyl halides through an S(N)2' substitution. Propargyl iodides as electrophiles are necessary to achieve good yields (36-95%) for most substrates, although the usefulness of chlorides and bromides is documented. A variety of monocyclic and bicyclic; vinylidene cycloproparies can be prepared. These products are not available by standard carbene methodology.
Palladium catalyzed divergent cycloadditions of vinylidenecyclopropane-diesters with methyleneindolinones enabled by zwitterionic π-propargyl palladium species
作者:Ben Niu、Yin Wei、Min Shi
DOI:10.1039/d1cc01453f
日期:——
spirooxindoles fused with a five- or a six-membered ring by a cycloaddition reaction of vinylidenecyclopropane-diesters with methyleneindolinones was disclosed. This protocol features an in situ generated unprecedented zwitterionic π-propargyl palladium species in cycloaddition reactions and a switchable process between (3+2) and (4+2) cycloadditions by changing the phosphine ligand.
1,3-Dipolar Cycloaddition Reactions of Vinylidenecyclopropane-Diesters with Aromatic Diazomethanes Generated in Situ
作者:Lei Wu、Min Shi
DOI:10.1021/jo100105k
日期:2010.4.2
1,3-Dipolarcycloaddition reactions of VDCP-diesters with aromatic diazomethanes generated in situ from the corresponding aromatic aldehydes and tosylhydrazine mediated by base produce pyrazole derivatives in good yields under mild conditions. A plausible reaction mechanism has been proposed on the basis of control experiments along with the discussion on the regioselectivity.
Cu-catalyzed C–C bond formation of vinylidene cyclopropanes with carbon nucleophiles
作者:Jichao Chen、Shang Gao、Ming Chen
DOI:10.1039/c9sc04122b
日期:——
The development of Cu-catalyzed addition of carbon nucleophiles to vinylidene cyclopropanes was reported. The reactions with 1,1-bisborylmethane provided homopropargylic boronate products by forming a C–C bond at the terminal carbon atom of the allene moiety of vinylidene cyclopropanes. Alkynyl boronates are also suitable nucleophile precursors in reactions with vinylidene cyclopropanes, and skipped
Cu-Catalyzed Silylation and Borylation of Vinylidene Cyclopropanes
作者:Jichao Chen、Shang Gao、Ming Chen
DOI:10.1021/acs.orglett.9b03354
日期:2019.11.1
silicon or boron nucleophiles to vinylidene cyclopropanes is reported. The reactions generated propargylic silane or boron products by forming a C-Si or C-B bond at the terminal carbon of the allene moiety of vinylidene cyclopropanes. The obtained silicon and boron reagents are versatile intermediates that can undergo a variety of transformations to give synthetically useful products. Preliminary mechanistic
Cu-catalyzed coupling of vinylidene cyclopropanes with allyl and allenyl boronates
作者:Ming Chen
DOI:10.1039/d1cc03823k
日期:——
Cu-catalyzed coupling of vinylidene cyclopropanes with allyl or allenyl boronates is reported. The reaction forms a C–C bond at the terminal carbon atom of the allene moiety of vinylidene cyclopropanes with concurrent opening of the cyclopropane ring. In addition, the resulting Cu-enolate intermediate can be intercepted by external electrophiles.
报道了亚乙烯基环丙烷与烯丙基或烯丙基硼酸酯的 Cu 催化偶联的发展。该反应在亚乙烯基环丙烷丙二烯部分的末端碳原子上形成 C-C 键,同时环丙烷环打开。此外,所得的 Cu-烯醇中间体可以被外部亲电试剂拦截。