m-CPBA/KOH:  An Efficient Reagent for Nucleophilic Epoxidation of gem-Deactivated Olefins

Abstract

The m-chloroperoxybenzoate anion (generated from m-CPBA and bases such as K(2)CO(3) or KOH) is a highly efficient nucleophilic epoxidating reagent for strongly deactivated olefins containing two electron-withdrawing groups at the same carbon, under mild conditions which affect neither other double bonds nor electrophilic oxidizable centers such as sulfoxides.

Regio- and Diastereoselective Synthesis of Novel Polycyclic Pyrrolo[2,1-a]isoquinolines Bearing Indeno[1,2-b]quinoxaline Moieties by a Three-Component [3+2]-Cycloaddition Reaction

“…[21][22][23] The reaction of isoquinolinium N-ylides with various activated alkynes or olefins constitutes an efficient method for the regio-and stereoselective synthesis of structurally complex pyrrolo[2,1-a]isoquinolines with multiple contiguous stereogenic centers that have many applications in medicinal chemistry and drug discovery. 24,25 For example, Yan and co-workers reported the synthesis of spiro[indoline-3,3′-pyrrolo[1,2a]isoquinolines] by a 1,3-dipolar cycloaddition reaction of N-phenacylquinolinium bromides with 3-phenacylideneoxindoles as dipolarophiles. 24 Because of the biological importance of pyrrolo[2,1a]isoquinolines and quinoxaline structures, and in continuation of related studies and our growing interest in developing 1,3-dipolar cycloaddition reactions, [26][27][28] we decided to synthesize spiroheterocycles containing both pyrrolo[2,1a]isoquinoline and quinoxaline moieties.…”

Stereoselective Cyclopropanation as a Way to 1‐Aminocyclopropane‐1‐phosphonic Acids: Rationale for Phosphoryl Group Migration

“…[11][12][13] Low selectivity during the formation of cyclopropane 9 evidenced that the approach of methyl iodide can occur from both sides with about the same probability. A possible explanation could be connected with the small size of the nitrile substituent and strong repulsion between the CN and SO dipoles, [14] which could change the conformation and configuration of the sulfinyl carbanion. Precoordination of the nitrile function, as postulated by the Knochel group, [15] can increase participation of structure C, which would result in the lack of selectivity observed in this case.…”

Synthesis of condensed isoxazolines and isoxazolidines via cycloaddition to furan-2(5H)-ones

“…1,3-Dipolar cycloadditions, by using nitrile oxides and nitrones as dipoles, are one of the best reported methods for building isoxazoline and isoxazolidine skeletons, respectively. 5,6 In an earlier work we reported the efficiency of 5-alkoxyfuran-2(5H)-ones as dipolarophiles in reactions with diazoalkanes, 7 alkyl-, bromo-or benzonitrile oxides, 8 azomethine ylides, 9 nitrones, 10 and carbonyl ylides. 11 One of the most significant features of adducts formed in these reactions is the versatility of their functionalities, which allows the subsequent synthesis of other heterocyclic systems, that are not easily obtained from other precursors.…”