Ring opening [3 + 2] cyclization of azaoxyallyl cations with benzo[d]isoxazoles: Efficient access to 2-hydroxyaryl-oxazolines

Publication date: February 2020Source: Chinese Chemical Letters, Volume 31, Issue 2Author(s): Yicheng He, Chao Pi, Yangjie Wu, Xiuling CuiAbstractA selective ring-opening [3 + 2] cyclization reaction of benzo[d]isoxazoles with 2-bromo-propanamides has been developed. The azaoxyallyl cation intermediates are employed as C∼O 3-atom synthon to build oxa-heterocycles via the selectivity of suitable cyclization partners. This transformation provides rapid access to highly functionalized 2-hydroxyaryl-oxazolines under mild conditions and excellent regioselectivity.Graphical abstractA novel and effective base-mediated one-pot synthesis of 2-hydroxyaryloxazolines starting from α-haloamides and benzo[d]isoxazoles under mild and simple conditions via ring opening of benzo[d]isoxazoles, selective [3 + 2] cycloaddition and H-transfer cascade reaction. The azaoxyallyl cation intermediates are employed as C∼O 3-atom synthon to build oxa-heterocycles.

Source: Chinese Chemical Letters - January 23, 2020 Category: Chemistry Source Type: research