N-thioacyl 1,3-amino alcohols: synthesis via ring-opening of oxiranes with thioamide dianions and applications as key intermediates leading to stereochemically defined 5,6-dihydro-4H-1,3-oxazines and 1,3-amino alcohols.
N-Thioacyl 1,3-amino alcohols were synthesized via the ring-opening of oxiranes with thioamide dianions generated from N-benzyl thioamides and BuLi in a highly regio- and stereoselective manner. The diastereomers of N-thioacyl 1,3-amino alcohols were readily separated by column chromatography to give stereochemically defined N-thioacyl 1,3-amino alcohols. They underwent intramolecular cyclization with Bu4F and EtI to give 5,6-dihydro-4H-1,3-oxazines. The reaction was specific with anti-N-thioacyl 1,3-amino alcohols, and cis-5,6-dihydro-4H-1,3-oxazines were obtained with high efficiency, whereas the reaction of a syn-alcohol gave a thioimidate as a major product. The reduction of N-thioacyl 1,3-amino alcohols with LiAlH4gave N-alkyl 1,3-amino alcohols in high yields. The use of optically active propylene oxide as a starting material gave the corresponding oxazine and alcohols in optically pure forms.
Murai
Toshiaki
T
Department of Chemistry, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan. mtoshi@cc.gifu-u.ac.jp
Sano
Hiroaki
H
Kawai
Hiroyasu
H
Aso
Hideo
H
Shibahara
Fumitoshi
F
D000605:Amino Alcohols / Q000138:chemical synthesis*; D000838:Anions; D008958:Models, Molecular; D008968:Molecular Conformation; D010078:Oxazines / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds; D013854:Thioamides / Q000737:chemistry*
D000605:Amino Alcohols; D000838:Anions; D010078:Oxazines; D013438:Sulfhydryl Compounds; D013854:Thioamides