Enantioselective Desymmetrization of 3-Substituted Oxetanes: An Efficient Access to Chiral 3,4-Dihydro-2H-1,4-benzoxazines
Viraj A. Bhosale, Martin Nigríni, Martin Dračínský, Ivana Císařová and Jan Veselý*
*Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague, Czech Republic,
Email: jan.vesely
natur.cuni.cz
V. A. Bhosale, M. Nigríni, M. Dračínský, I. Císařová, J. Veselý, Org. Lett., 2021, 23, 9376-9381.
DOI: 10.1021/acs.orglett.1c03419
see article for more reactions
Abstract
A chiral phosphoric acid (CPA) catalyzes a versatile transition metal/oxidant free synthesis of chiral 2H-1,4-benzoxazines through enantioselective desymmetrization of prochiral oxetanes (30 examples) in very good yield and high enantioselectivity under mild reaction conditions.
see article for more examples
Organocatalytic Openings of Oxetanes to Dihydro-2H-1,4-Benzoxazines
An oven-dried 4 mL vial was charged with corresponding oxetane (0.05 mmol) and toluene (0.5mL, c= 0.1 M), then organocatalyst (5 mol %, 0.0025 mmol) was added. Then the reaction was stirred at room temperature. Upon completion of the reaction, the resulting mixture was directly subjected to flash column chromatography.
Key Words
3,4-dihydro-2H-1,4-benzoxazines, organocatalysis
ID: J54-Y2021
