The Reaction of o‐Aminoacetophenone N‐Tosylhydrazone and CO₂ toward 1,4‐Dihydro‐2H‐3,1‐benzoxazin‐2‐ones

Abstract

A transition-metal-free reaction of oaminoacetophenone N-tosylhydrazone and CO 2 has been developed, leading to a series of 1,4-dihydro-2H-3,1-benzoxazin-2-ones in moderate to good yields. This procedure proceeds with the sequential fixation of CO 2 by amino leading to carbamic acid and the intra-molecular insertion of hydroxyl to carbene.

Who is Who in the Carbene Chemistry of N‐Sulfonyl Hydrazones

“…[ 196 ] On the other hand, the reaction of o ‐aminoacetophenone‐derived N ‐tosylhydrazone with carbon dioxide provided the 1,4‐dihydro‐2 H ‐3,1‐benzoxazin‐2‐ ones. [ 197 ] The reaction involves the sequential CO 2 fixation of the amino group leading to carbamic acid followed by the intramolecular carbene insertion of the hydroxyl group (Scheme 28b). They also demonstrated a palladium‐catalyzed three‐component reaction of N ‐tosylhydrazones with 2‐iodoanilines and CO 2 at atmospheric pressure, allowing access to diverse 4‐aryl‐2‐quinolinones.…”

Base-mediated carboxylation of C-nucleophiles with CO2

“…The carboxylative cyclization reaction of o -aminoacetophenone N -tosylhydrazone with CO 2 was subsequently realized in the presence of the base Cs 2 CO 3 . 78…”

Emerging Trends in N‐Tosylhydrazone Mediated Transition‐Metal‐Free Reactions

“…Cheng and co-workers [89] developed a new reaction method to synthesize 1,4-dihydro-2H-3,1-benzoxazine-2-one 68 derivatives using CO 2 as a C 1 source with N-tosylhydrazone 66. The Synthesis proceeds with sequential fixation of CO 2 by amino followed by origin of carbene from N-Tosylhydrazone and intramolecular insertion of hydroxyl in situ formed carbamic ChemistrySelect acid 67.…”