Further Insight into the Reactivity of Oxazinones Toward Phosphorus Reagents

Abstract

A series of quinoline derivates has been obtained from the reaction of 3‐phenyl‐2,4‐benzoxazin‐1‐one (1) with alkylidenephosphoranes. With ester ylides 3a,b, the reaction affords hydroxyquinolines 8a,b and new stable phosphorus ylide 9, whereas with keto ylides 3c,d, quinolinones 12a,b, hydroxyindoles 10a,b and benzoazepines 14a,b are obtained. 1 reacts with allyl‐4, methyl‐5a and ethyltriphenylphosphonium bromides 5b in the presence of LiH to afford 2‐hydrophenyloxazolo[1,2‐a]‐ 4‐hydroxyquinoline (16) from the first reaction whereas alkoxyquinolines 21a,b and hydroxyazepines 22a,b are obtained from 5a,b.

Keywords:

• 2,4‐Oxazin‐1‐one
• Quinolines
• Azepines
• Resonance‐stabilized
• Unsaturated and active alkylidenephosphoranes
• Intramolecular Wittig reaction