Intramolecular C–O/C–S bond insertion of α-diazoesters for the synthesis of 2-aryl-4H-benzo[d][1,3]oxazine and 2-aryl-4H-benzo[d][1,3]thiazine derivatives

Abstract

An intramolecular C–O/C–S insertion of 2-(2-arylamidophenyl)-2-diazoacetate/2-diazo-2-(2-arylthioamidophenyl)acetate is achieved using 10 mol% Cu(OTf)2 to generate benzoxazines/benzothiazines.

Progress in intermolecular and intramolecular reactions of thioamides with diazo compounds and azides

“…This furnished a small series of benzo[d] [1,3]-thiazines 25 in 75-80% yields. A plausible mechanism involves the insertion of a copper carbenoid into the thiocarbonyl group, leading to the formation of a thiocarbonyl ylide followed by an H-shift which finalizes the process (Scheme 8) [24].…”

Recent Advances in the Synthesis of 5‐MemberedN‐Heterocycles via Rhodium Catalysed Cascade Reactions

“…The carbene/alkyne metathesis (CAM) cascade reactions have received considerable attention due to their extraordinary efficiency for complex molecular synthesis [163a] . The key transformations of metal carbenes and secondary amides include N−H insertion and O−H insertion reactions [163b–e] . Recently, synthesis of 2‐aryl‐4 H ‐benzo[ d ][ 1,3 ]oxazine were reported by Reddy and group via O−H insertion reactions of secondary amides to donor/acceptor carbenoids through zwitter ionic intermediates [163e] .…”

“…The key transformations of metal carbenes and secondary amides include N−H insertion and O−H insertion reactions [163b–e] . Recently, synthesis of 2‐aryl‐4 H ‐benzo[ d ][ 1,3 ]oxazine were reported by Reddy and group via O−H insertion reactions of secondary amides to donor/acceptor carbenoids through zwitter ionic intermediates [163e] . An efficient rhodium‐catalyzed formal C−O insertion reaction of alkyne‐tethered diazo compounds 273 was developed by Jia and co‐workers, in 2019 to synthesize 3 H ‐indol‐3‐ols 274 .…”

Efficient Synthesis of Substituted 2-(4H-1,3-benzoxazin-2-yl)Phenols via a Pseudo Three-Component Reaction

“…Benzoxazine as a key structural motif exists in large numbers of pharmaceutically active compounds and biologically active natural products. [1][2][3][4][5] Benzoxazine derivatives exhibit anticancer, [6][7][8] antiobiotic, 9 antimicrobial, 10 antinflammatory, 11 antiplatelet 12,13 anticonvulsant 14 and anti-resorptive 15,16 activities. In light of the significance of benzoxazine derivatives and their diverse pharmacological properties, there has been a continuous effort to develop new, convenient and versatile methods for the synthesis of this class of compounds.…”