One-Pot Synthesis of Enantiopure Spiro[3,4-dihydrobenzo[][1,4]oxazine-2,3'-oxindole] via Regio- and Stereoselective Tandem Ring Opening/Cyclization of Spiroaziridine Oxindoles with Bromophenols.
Hajra, Saumen;Hazra, Atanu;Abu Saleh, S K;
The Journal of organic chemistry2019Vol. 84pp. 10412-10421
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hajra2019onepotthe
Abstract
A highly efficient regio- and stereoselective spiroaziridine ring opening with 2-bromophenols and a subsequent tandem cyclization reaction was developed for the one-pot synthesis of enantiopure 3,4-dihydrospiro[benzo[][1,4]oxazine-2,3'-oxindole] with excellent enantiopurity (ee up to >99%). It is further extended to asymmetric synthesis of NH-free 3,4-dihydrospiro[benzo[][1,4]oxazine-2,3'-xindole] retaining the optical activity