Since we have shown previously that 2-thia-1-azabicyclo[2.1.1]hexane derivative 3 is prone to ring system opening, we wanted to find out if compounds 4a-c tolerate typical organic transformations, as well as use the ester synthetic handle in its molecule to obtain a series of building blocks relevant to medicinal chemistry. These included reactions of ester 4a with strong nucleophilic agents such as alkali (providing carboxylic acid 16 in 95% yield) or LiAlH4 (giving primary alcohol 17 in 74% yield); transformation of compound 17 into sulfonates 18 and their further SN2 reactions with azide, fluoride, or iodide (albeit in the latter case, corresponding product 21 was obtained in moderate yield due to its limited stability), as well as Staudinger reduction of azide 19 into primary amine 22 (Scheme 5). Moreover, Weinreb amide 23 could be obtained from carboxylic acid 16 in 49% yield, and the bicyclic sultam core tolerated further reactions with MeMgBr or PhMgBr (Scheme 6). In addition to that, we synthesized aldehyde 26 via catalytic reduction of thioester 25 (52% yield over two steps), and it was compatible with the Wittig reaction conditions (providing alkene 27 in 81% yield) (Scheme 7). Meanwhile, deoxofluorination of compound 26 was accompanied by the sultam ring opening. We managed to isolate sulfonyl fluoride 28 in 23% yield from the reaction mixture, while target product 29 was not observed. Synthetic transformations of diester 4c included its reduction with LiAlH4 giving diol 30 (60% yield) that was transformed into interesting tricyclic pyrrolidine derivative 32 via double mesylation (97% yield) and further amination with p-methoxybenzylamine (68% yield) (Scheme 8). In conclusion, intramolecular flow photochemical [2 + 2] cycloaddition is a very straightforward and efficient approach to the multigram preparation of 2-thia-3-azabicyclo[2.1.1]hexane 2,2dioxides. This scaffold is the smallest possible bridged sultam containing carbon atoms at the bridgehead positions and a promising isostere of pyrrolidine, pyrrolidone, and monocyclic -sultams. The title bicyclic ring system tolerates many typical organic reaction conditions, including alkaline ester hydrolysis, reduction with LiAlH4, reactions with organometallic reagents, etc., although it is unstable towards certain reagents like Morph-DAST. Therefore, the 2-thia-3-azabicyclo[2.1.1]hexane 2,2-dioxide scaffold can be easily decorated with various functional groups, thus providing valuable chemotypes for early drug discovery programs.