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 1 was heated with triethyl or triisopropyl phosphite at 100deg;C whereas at 170deg;C 7 was obtained as the major product (∼53%). 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 . © 2003 Wiley Periodicals, Inc. 15:77–84, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.10216