Magnesium Catalysis Mediated Tetrazoles in Desymmetrization Reaction of Aziridines

Abstract

A magnesium-catalyzed asymmetric ring-opening reaction of aziridines with substituted tetrazoles is reported. The current protocol proceeds smoothly and gives the corresponding desymmetrization products in high yields and good enantioselectivities. A new chiral ligand was synthesized from azetidine and (R)-BINOL and was employed in the current in situ generated magnesium catalyst. The Mg(II)-mediated desymmetrization reaction could be performed on gram scale under mild conditions and was transformed to chiral alkyl amines by a deprotection process.

Synthesis of chiral pyridine-oxazolines via a catalytic asymmetric Heine reaction of meso-N-(2-picolinoyl)-aziridines

“…The chiral catalyst promoted reaction of 1q proceeded well, implying that the S N i mechanism is dominant, and the anion-involved S N 2 mechanism could be ruled out in this system, 17 and it is also different from previous intermolecular desymmetric processes. [6][7][8][9][10][11][12][13] Based on the absolute configuration of the product 2a and the single-crystal structure of the catalyst L 3 -RaEt 2 /Yb(OTf ) 3 , 18 possible work modes to unveil the enantiocontrol are provided in Scheme 3d. Initially, the chiral Yb(III) catalyst bonds 2-picolinoyl-aziridine 1a with the two nitrogens, and the pyridine ring is located above the bicyclic ring of the ligand where CH-π interaction could stabilize the state to extend based on our previous study.…”

Magnesium Catalysis in Asymmetric Synthesis

“…The azetidine ring on the ligand was thought to act as a Brønsted base to activate the tetrazole (Scheme 31). 72 The in-situ-generated magnesium catalysts with this type of ligand might serve as a bifunctional catalyst, making it more effective than the other complexes with different ligands that were tested in this study.…”

Chiral Magnesium(II) Complex‐Catalyzed Enantioselective Desymmetrization of meso‐Aziridines with Pyrazoles

“…During our preparation of this manuscript, Wang's group reported the desymmetrization of aziridines with tetrazoles under the catalysis which azetidine and ( R )‐BINOL was employed in situ generated magnesium complex . Given the remarkable efficiency of the present catalyst system, its further applicability was also examined with more azole derivatives (Scheme ).…”

“…[17] Given the remarkable efficiency of the present catalyst system, its further applicability was also examined with more azole derivatives (Scheme 1). [17] Given the remarkable efficiency of the present catalyst system, its further applicability was also examined with more azole derivatives (Scheme 1).…”