title: Cobalt-catalyzed asymmetric cyclopropanation with diazosulfones: rigidification and polarization of ligand chiral environment via hydrogen bonding and cyclization.
abstract: A new D2-symmetric chiral porphyrin P6 (2,6-DiMeO-ZhuPhyrin) with enhanced chiral rigidity and polarity was designed and synthesized through incorporation of hydrogen bonding and cyclic structure. Its cobalt(II) complex [Co(P6)] is a highly active and selective catalyst for asymmetric cyclopropanation of alkenes with diazosulfones. The [Co(P6)]-based catalytic system is suitable for various aromatic olefins as well as electron-deficient olefins, including alpha,beta-unsaturated esters, ketones, and nitriles, forming the corresponding cyclopropyl sulfones under mild conditions in high yields and high selectivities. In most cases, both excellent diastereo- and enantioselectivities were achieved.
authors: Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250, USA.
authors: Shifa
authors: S
authors: Zhu
authors: Joshua V
authors: JV
authors: Ruppel
authors: Hongjian
authors: H
authors: Lu
authors: Lukasz
authors: L
authors: Wojtas
authors: X Peter
authors: XP
authors: Zhang
mesh_terms: D000475:Alkenes / Q000737:chemistry; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D003500:Cyclization; D003521:Cyclopropanes / Q000737:chemistry*; D003979:Diazonium Compounds / Q000737:chemistry*; D006860:Hydrogen Bonding; D007477:Ions / Q000737:chemistry; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry; D013237:Stereoisomerism; D020058:Styrene / Q000737:chemistry; D013425:Sulfanilic Acids / Q000737:chemistry*; D013450:Sulfones / Q000737:chemistry*
chemical_list: D000475:Alkenes; D003521:Cyclopropanes; D003979:Diazonium Compounds; D007477:Ions; D008024:Ligands; D011166:Porphyrins; D013425:Sulfanilic Acids; D013450:Sulfones; D003035:Cobalt; D020058:Styrene; C030797:cyclopropane; C000469:diazobenzenesulfonic acid