Phosphono-substituted isoindolines and indoles from 2,3-and 2,4-benzoxazin-1-ones

Reactions of 2,3-benzoxazinone 1 and 2,4-benzoxazinone 2, with trialkyl phosphites 3a-c provide access to new phosphono-substituted isoindolines 6a-f and indoles 19a-e, respectively. Phosphono-substituted 2,3-benzoxazines 5a-c were also obtained in the first reaction. Bisisoindolinylidene (7) was, however, isolated in low yields when I was heated with triethyl or triisopropyl phosphite at 100degreesC whereas at 170degreesC 7 was obtained as the major product (similar to53%). On the other hand, the reaction of 1 or 2 with dialkyl phosphonates 4a-c proceeded in the presence of aqueous solution of NaOH (5%) to give the respective alkylated product 14a-c or 20a-c. (C) 2003 Wiley Periodicals, Inc.