Enantiopure 1,4-benzoxazines via 1,2-cyclic sulfamidates. Synthesis of levofloxacin.
1,2-Cyclic sulfamidates undergo efficient and regiospecific nucleophilic cleavage with 2-bromophenols (and related anilines and thiophenols), followed by Pd(0)-mediated amination to provide an entry to substituted and enantiomerically pure 1,4-benzoxazines (and quinoxalines and 1,4-benzothiazines). This chemistry provides a short and efficient entry to (3S)-3-methyl-1,4-benzoxazine 19, a late stage intermediate in the synthesis of levofloxacin.
Bower
John F
JF
School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
Szeto
Peter
P
Gallagher
Timothy
T
D000890:Anti-Infective Agents / Q000138:chemical synthesis; D048588:Benzoxazines / Q000737:chemistry; D064704:Levofloxacin; D015242:Ofloxacin / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013449:Sulfonamides / Q000737:chemistry
D000890:Anti-Infective Agents; D048588:Benzoxazines; D013449:Sulfonamides; D064704:Levofloxacin; D015242:Ofloxacin