Cobalt-catalyzed asymmetric cyclopropanation with diazosulfones: rigidification and polarization of ligand chiral environment via hydrogen bonding and cyclization.
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.
Zhu
Shifa
S
Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250, USA.
Ruppel
Joshua V
JV
Lu
Hongjian
H
Wojtas
Lukasz
L
Zhang
X Peter
XP
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*
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