Regiospecific lithiation of phenoxazine ortho to the oxygen atom. Synthesis of 4-mono-and 4, 6-disubstituted phenoxazine derivatives

Y Antonio, P Barrera, O Contreras…

文献索引：Antonio, Yulia; Barrera, Patricia; Contreras, Olga; Franco, Fidencio; Galeazzi, Edvige; et al. Journal of Organic Chemistry, 1989 , vol. 54, # 9 p. 2159 - 2165

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被引用次数: 9

摘要

Under appropriate conditions, phenoxazine bearing a sterically demanding, bulky N- substituent (eg, a-methylbenzyl or tert-butyldimethylsilyl) undergoes lithiation at C-4 or at C- 4 and C-6 with n-butyllithium in THF solution. The lithiated species react with a variety of electrophilic reagents and upon subsequent N-deprotection provide access to 4-mono-or 4, 6-disubstituted phenoxazines. This process is of particular synthetic utility (36-54% yields) ...