To date, only a single cationic trypticene analogue with a sulfur atom at its bridgehead position was reported. This compound (Scheme 1d) was synthesized via a formal [4+2] cycloaddition of a benzyne synthone to a thioxanthone. We therefore hypothesized that an analogous bicyclic scaffold could also be prepared from a bisphosphineoxide-functionalized thioxanthone derivative 1 (Scheme 3a), which we had reporter earlier. Indeed, treating 1 with 2-(trimethylsilyl)phenyl triflate in presence of TBAF led to the formation of a cycloaddition product, [2](OTf). This transformation was immediately apparent from the absence of the characteristic carbonyl stretch in IR at ca. 1630 cm -1 , as well as the appearance of 4 new 1 H NMR signals (vide infra), attributed to the newly added arene moiety (Figure ). Concurrently, the lowest field signal in C NMR corresponding to the carbonyl carbon of 1 shifted nearly 100 ppm upfield (as verified by the 1 H C HMBC, see Fig. ). Protecting the tertiary alcohol group in [2](OTf) as a methyl ether, followed by phosphine oxide reduction, afforded the desired bicyclic ligand The 1 H NMR of [4](OTf) revealed the benzyne-derived arene group (protons a-d) as a set of four distinct signals at = 8.05, 7.58, 7.09, and 6.05 ppm showing strong cross-correlations in 1 H-1 H COSY spectrum (Figure ). In addition, the bridgehead carbon resonating at = 88.6 ppm in C NMR showed a clear correlation in 1 H C HMBC with both the methoxy protons (= 4.38 ppm) and the aromatic protons e (= 8.05 ppm) of [4](OTf) (Figure ).