[2 + 2] Annulation of Aldimines with Sulfonic Acids: A Novel One‐Pot cis‐Selective Route to β‐Sultams

Abstract

A novel DMF/dimethyl sulfate promoted [2 + 2] annulation of aldimines with sulfonic acids afforded β-sultams in good to excellent yields (35-93 %) under mild conditions. The pro-

A Simple and One‐Pot Synthesis of β‐Sultams by Using the Vilsmeier Reagent

“…Column chromatography was performed on Merck Kiesel gel (230–270 mesh). Compounds 9a , 9b , 9c , 9d , 9e , 9f , 9g , 9h , 9i , 9j , 9k were known, and their spectral data have been previously reported [6a, 19b,c, 27].…”

“…Indication of stereochemistry of the β‐sultam 9a was deduced from the coupling constant of H‐3 and H‐4, which were calculated to be J = 8.6 Hz for the cis ‐stereoisomer. The β‐sultam ring is more distorted than the β‐lactam ring, which presumably causes a decrease in its outer H–C–C bond angles and results in the higher J value of the cis ‐configured β‐sultams than the corresponding β‐lactams .…”

“…We utilized alkoxymethylene‐ N,N ‐dimethyliminium salts as acid activators in the synthesis of 2‐azetidinone ring by the ketene‐imine cycloaddition . In a recent communication, Yadav and co‐workers used this reagent in the synthesis of β‐sultams from imines with sulfonic acids . Previously, we reported the synthesis of 2‐azetidinone from imines and carboxylic acids via the Vilsmeier reagent ((chloromethylene)dimethylammonium chloride) .…”

Advances in amidation chemistry – a short overview

“…DMF, for example, can be used as an effective ligand in the production of metallic complexes. 1 In addition to acting as a source of various important intermediates, DMF can react as an electrophile or a nucleophile and can play a role in reactions as a dehydrating agent, a reducing agent, a catalyst, [2][3][4][5] or a stabilizer. [6][7][8][9] For the synthesis of metallic compounds DMF can be an effective ligand.…”

Peculiar Wetting of N,N-Dimethylformamide: Expansion, Contraction, and Self-Running

“…It has a high boiling point (154 °C) and thus exhibits low vapor pressure (<4 mmHg) at room temperature. Because DMF can dissolve most organic compounds owing to its polar aprotic characteristics, it is frequently used as a solvent for preparation of colloids, − synthesis of block copolymers, , and electrospinning, , in addition to common chemical reactions. − Apart from being a solvent, the utilities of DMF as reagents, , catalysts, , and stabilizers − have been also well established. Furthermore, DMF is frequently taken as a suspending medium or buffer solution in microfluidic devices over recent decades. , Although DMF has shown multipurpose applications, its wetting behavior on solid substrates (particularly total wetting surfaces) is still veiled.…”