Study of Insertion Reactions with Phosphorus Ylides − On Reactions between 4-(4-Methylphenyl)-2,3-benzoxazin-1-one and Alkylidene Phosphoranes

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

“…In summary, the findings from the reactions of 2,3-oxazinone 1 with alkyl phosphites, which have been reported in the present investigation, or with alkylidene phosphoranes that were reported in the earlier work [8], highlight the initial attack by the nucleophilic tri-and pentavalent phosphorus reagents on the carbonyl-carbon in 1. However, the mode of further transformations would vary with the electronic characteristics of the phosphorus reagent.…”

“…Schemes 2 and 3 try to explain the observed reactions. The primary nucleophilic attack [8,9] of the phosphite on C-1, with subsequent ring opening of 1, gives the zwitterion 8 [8,9]. Stabilization of 8 may be attained in two different ways.…”

“…However, the mode of further transformations would vary with the electronic characteristics of the phosphorus reagent. Considering the previous report [8], the common feature of the reactions of phosphorus ylides with 1 seemed to be proceeding via an ionic mechanism. Conversely, the involvement of the carbene intermediate in the reactions of 1 with TAP is the driving force for the formation of the final products 5-7.…”

“…In a recent study [8], we described the synthesis of several isoquinoline derivatives of pharmaCorrespondence to: Wafaa M. e-mail: wabdou@ intouch.com. c 2003 Wiley Periodicals, Inc. cological value by treating 4-(4-methylphenyl)-2,3-benzoxazin-1-one (1) with different types of alkylidenephosphoranes.…”

Heterocycles as versatile building blocks in different synthetic strategies

“…When 3b reacted with (methoxycarbonyl) methylenetriphenyl phosphorane 25a in boiling toluene in the presence of triethylamine, methyl 1-(4-methylphenyl)4-oxo-3H-isoquinoline-3-carboxylate 26a was obtained in 74% yield 10 . Similarly, treatment of 3b with 25b afforded 26b in 68% yield.…”