4548-34-9Relevant articles and documents
Diastereoselective Photoredox-Catalyzed [3 + 2] Cycloadditions of N-Sulfonyl Cyclopropylamines with Electron-Deficient Olefins
White, Dawn H.,Noble, Adam,Booker-Milburn, Kevin I.,Aggarwal, Varinder K.
supporting information, p. 3038 - 3042 (2021/05/04)
A highly diastereoselective, visible-light-induced [3 + 2] cycloaddition between N-sulfonyl cyclopropylamines and electron-deficient olefins is reported. The reactions proceed via the oxidation of a sulfonamide aza-anion by an organic photocatalyst to generate a nitrogen-centered radical. Strain-induced ring opening and intermolecular addition to the olefin generate an intermediate carbon-centered radical that is reduced to an anion prior to 5-exo cyclization. This enables a highly diastereoselective construction of trans-cyclopentanes possessing synthetically useful functional groups.
Gram-Scale Synthesis of Chiral Cyclopropane-Containing Drugs and Drug Precursors with Engineered Myoglobin Catalysts Featuring Complementary Stereoselectivity
Bajaj, Priyanka,Sreenilayam, Gopeekrishnan,Tyagi, Vikas,Fasan, Rudi
, p. 16110 - 16114 (2016/12/26)
Engineered hemoproteins have recently emerged as promising systems for promoting asymmetric cyclopropanations, but variants featuring predictable, complementary stereoselectivity in these reactions have remained elusive. In this study, a rationally driven strategy was implemented and applied to engineer myoglobin variants capable of providing access to 1-carboxy-2-aryl-cyclopropanes with high trans-(1R,2R) selectivity and catalytic activity. The stereoselectivity of these cyclopropanation biocatalysts complements that of trans-(1S,2S)-selective variants developed here and previously. In combination with whole-cell biotransformations, these stereocomplementary biocatalysts enabled the multigram synthesis of the chiral cyclopropane core of four drugs (Tranylcypromine, Tasimelteon, Ticagrelor, and a TRPV1 inhibitor) in high yield and with excellent diastereo- and enantioselectivity (98–99.9% de; 96–99.9% ee). These biocatalytic strategies outperform currently available methods to produce these drugs.
Stereodivergent synthesis of arylcyclopropylamines by sequential C-H borylation and Suzuki-Miyaura coupling
Miyamura, Shin,Araki, Misaho,Suzuki, Takayoshi,Yamaguchi, Junichiro,Itami, Kenichiro
supporting information, p. 846 - 851 (2015/02/19)
A step-economical and stereodivergent synthesis of privileged 2-arylcyclopropylamines (ACPAs) through a C-(sp3)-H borylation and Suzuki-Miyaura coupling sequence has been developed. The iridium-catalyzed C-H borylation of N-cyclopropylpivalamide proceeds with cis selectivity. The subsequent B-cyclopropyl Suzuki-Miyaura coupling catalyzed by [PdCl2(dppf)]/Ag2O proceeds with retention of configuration at the carbon center bearing the Bpin group, while epimerization at the nitrogen-bound carbon atoms of both the starting materials and products is observed under the reaction conditions. This epimerization is, however, suppressed in the presence of O2. The present new ACPA synthesis results in not only a significant reduction in the steps required for making ACPA derivatives, but also the ability to access either isomer (cis or trans) by simply changing the atmosphere (N2 or O2) in the coupling stage.
