Convenient Preparation of N-Acylbenzoxazines from Phenols, Nitriles, and DMSO Initiated by a Catalytic Amount of (COCl)₂

Abstract

A convenient preparation method of N-acylbenzoxazines has been developed, in which phenols react with nitriles and dimethyl sulfoxide (DMSO) in the presence of a catalytic amount of (COCl)2 in CH3CN or chloroform to afford the corresponding N-acylbenzoxazines in moderate-to-good yields. DMSO acts as a source of HCHO, which is generated in situ from the decomposition of a methoxydimethylsulfonium salt. A regeneration cycle of the methoxydimethylsulfonium salt is proposed, which is initiated by a catalytic amount of (COCl)2.

Convenient Preparation of 2,4‐Dithiapentane, Dimethyl Disulfide, and the Corresponding Deuterated Products from DMSO or [2H6]‐DMSO/(COCl)2

“…The combined reagent, DMSO/(COCl) 2 , is widely used as an oxidant for the oxidation of alcohols, in which the chlorodimethylsulfonium salt is the key active species [15] . In our recent studies about the application of sulfoxide/oxalyl halide in various transformations, it was found that DMSO/(COCl) 2 is quite versatile and can generate various active species in situ , such as CH 3 SCl, [16–18] HCHO, [19] or act as a source of Cl + [20] . We also established a practical preparation method of methyl methanethiosulfonate using DMSO in the presence of catalytic amount of (COCl) 2 [21] .…”

A Convenient Method for α‐Chlorination of 1,3‐Diketones and β‐Keto Esters with DMSO or Ph2SO/(COCl)2

“…We have been exploring new methodologies using the combination of sulfoxide/(COX) 2 in various organic transformations recently. Several synthetic methods have been developed, [15] including sulfenyllactonization [15a] or chlorolactonization [15b] of alkenoic acids, bromination of alkenes, [15c] dehydration of primary amides or aldoximes, [15d] dichlorination of alkenes, [15e] and the preparation of benzoxazines [15f] . Encouraged by the results of chlorolactonization of alkenoic acids and dichlorination of alkenes with Ph 2 SO/(COCl) 2 , we envisioned that it might be practical for the chlorination of 1,3‐dicarbonyls with sulfoxide/(COCl) 2 .…”