Synthesis of 1-Acyl-2-vinylcyclopropanes: Utilizing Copper-Carbenoid versus Sulfur Ylide Methodology

Abstract

The synthesis of a range of racemic 1-acyl-2-vinylcyclo­propanes by using two different methodologies is studied. We have developed a copper-catalyzed process for converting diazoketones into 1-acyl-2-vinylcyclopropanes and a sulfur-ylide-mediated procedure which allows, in only two steps, a simplified access to 1-acyl-2-vinyl­cyclopropanes with alkyl or aryl substituents on the alkene moiety.

Formal allylic C(sp3)–H alkylation of α-alkylstyrenes by rearrangement of intermediate alkenyl sulfonium salts

“…Based on the literature 13 and the experimental results, a proposed mechanism rationale for this transformation is described in Scheme 6. In the presence of a base, the isomerization of alkenyl sulfonium salt ( 1 or 2 ) to allylic sulfonium salt A occurs, followed by deprotonation of alkyl sulfonium salt A to generate intermediate B , which undergoes a [2,3]-sigmatropic rearrangement to give the desired product 3 or 4 .…”

Development of a Cyanide‐free and Scalable Route for the ADAMTS‐5 Inhibitor GLPG1972: Synthesis of an Advanced Key Chiral Intermediate

“…Briefly, ethyl 4-bromobutyrate 6 was transformed to known phosphonium salt 7. [18] The treatment of phosphonium salt with the ketone 8 in presence of potassium tert-butoxide afforded the Wittig product 9 in good yields. The 1 H NMR and mass data confirmed the formation of compound 9.…”