DMSO as a Dual Carbon Synthon and Water as Oxygen Donor for the Construction of 1,3,5-Oxadiazines from Amidines

Abstract

A selective and efficient synthesis of diaryl 1,3,5-oxadiazines was established for the first time from simple and readily available amidines in wet DMSO. DMSO was employed as a dual carbon synthon and water offered the oxygen atom to construct the oxadiazine ring. The reaction involved two new C–N and two new C–O bond formations.

Modification of Pyrrolo[2,1‐a]isoquinolines through Iron‐Catalyzed Aminomethylenation with Amines and Dimethyl Sulfoxide

“…Surprisingly, it was found that Cu(OTf) 2 can catalyse this reaction in a catalytic version instead of using stoichiometric amount of other activators, albeit with a low yield (14 %, entry 10). Previously, this copper salt has been used as a catalytic activator of DMSO for formylation of indoles by Chiba and co‐workers [2d,4g,5d–e] . But it was not effective enough for aminomethylenation as a catalyst in this process.…”

“…Activators must activate DMSO to yield active species and simultaneously avoid side reactions with starting material, other intermediates and products. In particular, catalytic activation of DMSO has been rarely reported so far [2d,4g,5d–e] . Stoichiometric amount of activator should be used in most cases of DMSO‐based reaction systems.…”

Selectfluor-Mediated Synthesis of β-Acyl Allyl Sulfones/β-Acyl Allyl Benzotriazoles from Ketones/Acetylenes, Aryl Sulfinates/Benzotriazole, and DMSO as a Dual-Carbon Synthon

“…There are limited reports on DMSO being a dual-carbon synthon in organic transformations . Recently, Ma and co-workers described the synthesis of copper­(II)-catalyzed, Selectfluor-mediated 1,3,5-oxadiazines from amidines, DMSO, and H 2 O, where DMSO was employed as a dual-carbon synthon . In particular, Selectfluor-mediated transition metal-free transformations wherein DMSO acts as a dual-carbon synthon have not been realized yet.…”

Direct Assembly of Polysubstituted Furans with Dimethyl Sulfoxide as a Multipurpose Precursor via β‐C(sp3)−H Functionalization of Saturated Ketones

“…Undesirable results were observed when reducing or increasing the temperature (entries 11, 12). It is worth noting that the yield of the product was decreased when changing the loading of K 2 S 2 O 8 (entries [13][14].…”