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

Autor: Sang‐gi Lee, U. Bin Kim, Da Jung Jung, Young Ok Ko, Hyun Ji Jeon
Rok vydání: 2016
Předmět:
Zdroj: Organic Letters. 18:6432-6435
ISSN: 1523-7052
1523-7060
DOI: 10.1021/acs.orglett.6b03328
Popis: 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.
Databáze: OpenAIRE