title: Rh(II)/Mg(OtBu)2-Catalyzed Tandem One-Pot Synthesis of 1,4-Oxazepines and 1,4-Oxazines from N-Sulfonyl-1,2,3-triazoles and Glycidols.
abstract: A novel, one-pot route for the synthesis of nonaromatic ring-fused 1,4-oxazepines and 1,4-oxazines has been developed. The reaction features a sequential rhodium(II)-catalyzed reaction of N-sulfonyl-1,2,3-triazoles with glycidols, followed by a regioselective Lewis acid Mg(OtBu)2-catalyzed intramolecular ring-opening reaction. It has been found that the regioselectivity in the epoxide ring-opening was largely determined by the substituents on the glycidols. Thus, substituted glycidols (R2≠ H) afforded seven-membered oxazepine derivatives selectively, while unsubstituted glycidols (R2= H) afforded six-membered oxazine derivatives. Plausible reaction pathways are elucidated and supported by experiments with several glycidols bearing different substituents around the epoxide functionality.
authors.affiliation: Department of Chemistry and Nano Science (BK Plus), Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Young Ok
authors.initials: YO
authors.lastname: Ko
authors.affiliation: Department of Chemistry and Nano Science (BK Plus), Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Hyun Ji
authors.initials: HJ
authors.lastname: Jeon
authors.affiliation: Department of Chemistry and Nano Science (BK Plus), Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Da Jung
authors.initials: DJ
authors.lastname: Jung
authors.affiliation: Department of Chemistry and Nano Science (BK Plus), Ewha Womans University , Seoul 120-750, Korea.
authors.forename: U Bin
authors.initials: UB
authors.lastname: Kim
authors.affiliation: Department of Chemistry and Nano Science (BK Plus), Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Sang-Gi
authors.identifier: 0000-0003-2565-5233
authors.initials: SG
authors.lastname: Lee