Stereoselective [3+2] cycloaddition of N-tert-butanesulfinyl imines to arynes facilitated by a removable PhSO₂CF₂ group: synthesis and transformation of cyclic sulfoximines

Abstract

An unprecedented [3+2] cycloaddition between N-tert-butanesulfinyl imines and arynes provides a stereoselective method for the synthesis of cyclic sulfoximines. Not only does the difluoro(phenylsulfonyl)methyl group play an important role in facilitating the cycloaddition reaction, it can also be removed or substituted through the transformation of the difluorinated cyclic sulfoximines to cyclic sulfinamides.

Sigmatropic Rearrangement of Vinyl Aziridines: Expedient Synthesis of Cyclic Sulfoximines from Chiral Sulfinimines

“…Thes ulfoximine 3e was isolated in 49 %y ield following the one-pot procedure compared to the 33 %o verall yield observed for the two-step method. [22] Furthermore,t he less reactive tert-butylsulfinimines (entries 3-7) were efficiently converted into the corresponding sulfoximines using this new protocol, although it was noted that these products were prone to thermal elimination of the tert-buyl group (this process was also noted by Hu and co-workers [13] in their cyclic sulfoximines). We also found that the method is compatible with less common sulfinimines such as biphenyl-or 3,5-bistrifluoromethylphenyl sulfinimine, which can be conveniently synthesised in one step from the parent aldehyde [14c] (entries 9a nd 10).…”

“…[12] Furthermore, they generally describe benzofused cyclic sulfoximines.T his limitation is found in the recent work reported by Hu et al where avery elegant one-step synthesis of cyclic sulfoximines was achieved, starting from enantiomerically pure sulfinimines,bycycloaddition with benzynes. [13] Herein we describe as imple and versatile method for the synthesis of nonfused six-membered cyclic sulfoximines with complete diastereocontrol and aw ide substrate range.…”

Efficient Synthesis of Cyclic Sulfoximines from N‐Propargylsulfinamides through Sulfur–Carbon Bond Formation

“…Among sulfoximines, cyclic ones belong to an underutilized class of heterocycles, whose potential biological properties remain largely unexplored. Only a few methods including the 3+2 cycloaddition between N‐sulfinylimines and in situ generated benzynes and the sigmatropic rearrangement of N‐sulfinyl‐2‐vinylaziridines have so far been reported to produce cyclic sulfoximines from sulfinamide starting materials (Scheme b) . Very recently, Poisson et al.…”

“…The yield of 6 was improved to 66 % by using K 2 CO 3 as base at higher temperature. Cyclic sulfoximine ( R )‐ 3 a was converted to cyclic sulfinamide ( R )‐ 7 in good yield by treatment with HCl in methanol; however, this de‐ tert ‐butylation resulted in significant erosion of optical purity (Scheme c, Conditions A) . On the other hand, ( R )‐ 7 was obtained with high optical purity by treatment of ( R )‐ 3 a with BF 3 ⋅OEt 2 in the absence of water (Conditions B), and the present cyclization could be used for the asymmetric synthesis of cyclic sulfinamide.…”

“…the sigmatropic rearrangement of N-sulfinyl-2-vinylaziridines have so far been reported to produce cyclic sulfoximinesf rom sulfinamide startingm aterials (Scheme 1b). [8,9] Very recently, Poisson et al have reported the transition metal Lewis acid-catalyzed cyclic sulfoximine synthesis using specific N-propargylsulfinamideswith an alkoxy group at the alkyne terminus. [10] We became interested in developing ag eneral and efficient methodf or the synthesis of cyclic sulfoximines.…”