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Two Rearrangement Pathways in the Geminal Acylation of 2‐Methoxyoxazolidines Leading to Substituted 1,4‐Oxazines
Author(s) -
Moulins Jonathan R.,
Hughes Jeremy A.,
Doyle Lauren E.,
Cameron T. Stanley,
Burnell D. Jean
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201403371
Subject(s) - geminal , chemistry , acylation , cyclopentenone , cyclohexenone , cleavage (geology) , aldol reaction , oxazines , carbonyl group , acyl group , stereochemistry , medicinal chemistry , organic chemistry , group (periodic table) , catalysis , geotechnical engineering , fracture (geology) , engineering
Lewis acid‐mediated geminal acylation of 2‐methoxyoxazolidines with five‐ or six‐membered acyloins followed by heterocyclization afforded 1,4‐oxazines fused to cyclopentenone or cyclohexenone rings. Overall yields ranged from 30 to 73 %. The position of the carbonyl group in the products depended on whether or not water was present during the ring‐expanding acyl migration step. The route lacking water during the acyl migration step was best conducted in one pot. The addition of water effected cleavage of a silyloxy group in the intermediate during the initial Mukaiyama aldol reaction prior to the acyl migration.