New electrophilic fluoroalkylating agents based on the sulfoximine skeleton as a common platform are described. We demonstrate the importance of the activating group, attached to the nitrogen, and its specificity for the fluorinated group to be delivered. As an application, a variety of unknown dichlorofluoro, bromodifluoro, and trifluoromethyl alkynes have been prepared using these reagents.

Abstract:We have successfully extended our previously described methodology for the preparation of trifluoromethyl N-acyl sulfilimines to the case of bromodifluoro-and dichlorofluoromethyl derivatives. Attempts to convert such N-acyl sulfilimines to free NH-sulfilimines failed. However, a strategy based on the reaction of their direct ditriflyl ketal precursor with amines allows the isolation of either original sulfilimino iminium salts using secondary amines or of free NH-sulfilimines using primary amines. The latter were further easily N-functionalized with electron-withdrawing groups giving structures close to those of efficient perfluoroalkylating agents. Preliminary experiments showed that these new sulfiliminebased compounds have poor perfluoroalkylating abilities, demonstrating that the sulfilimine function is not sufficiently activating for that purpose, contrary to sulfur(VI) reagents.

We describe herein our progress toward the synthesis of halicyclamine A, which possesses very interesting biological activities and has never been synthesized. For this purpose, we proposed a stereoselective Diels-Alder reaction as a key step for the establishment of the stereogenic triad of the bis(piperidinyl) core of this molecule. A series of NMR studies was then conducted to establish the correct stereochemical assignment subsequent to the Diels-Alder reaction.

No abstract