Synthesis, bridgehead functionalization, and photoisomerization of 9,10-diboratatriptycene dianions

Abstract

9,10-Diboratatriptycene salts M2[RB(μ-C6H4)3BR] (R = H, Me; M+ = Li+, K+, [n-Bu4N]+) have been synthesized via [4+2] cycloaddition between doubly reduced 9,10-dihydro-9,10-diboraanthracenes M2[DBA] and benzyne, generated in situ from C6H5F...

The Field of Main Group Lewis Acids and Lewis Superacids: Important Basics and Recent Developments

“…Free 49 is unstable, but its complex with two SMe 2 molecules was isolated and structurally characterized. [200] High Lewis acidity of 49 is revealed in a short BÀ S bond distances in Me easily exchanges H À forming [ClB(C 6 H 4 ) 3 BCl] 2À . [200] Photoisomerization of K 2 [HB(C 6 H 4 ) 3 BH] to the 8,12B-dihydro-8,12B-diborabenzj[a]fluoranthene derivative in THF was studied experimentally and computationally.…”

“…[200] High Lewis acidity of 49 is revealed in a short BÀ S bond distances in Me easily exchanges H À forming [ClB(C 6 H 4 ) 3 BCl] 2À . [200] Photoisomerization of K 2 [HB(C 6 H 4 ) 3 BH] to the 8,12B-dihydro-8,12B-diborabenzj[a]fluoranthene derivative in THF was studied experimentally and computationally. [200] In 2022, two cationic boratripticene-like LA 50 and 51 (Scheme 24) based on the pyrazanole-bridged ansa-ferrocene were reported and structurally characterized by Wagner group (Scheme 24).…”

A focus on anionic boron anthracenes and triptycenes as entry point toward B-doped polyaromatic materials and Lewis acids

“…3 Recent efforts by Wagner and collaborators led to the rst doping of the two bridgehead positions of the unique paddlewheel shaped triptycene D 3h -symmetric scaffold by two boron atoms. 4 Analogously to the seminal Wittig synthesis of triptycene 2 by cycloaddition between anthracene 1 and in situ generated benzyne (Scheme 2a), 5 A key advance in boron chemistry is the photorearrangement of the diboratotriptycene 4-H into a diborabenzo[a]uoranthene 5 which combines the two prominent structural motifs of 9,10dihydro-9,10-diboraanthracene and 9H-9-borauorene (Scheme 4a). Such photorearrangements are following similar cascade steps as in the corresponding allcarbon triptycene derivative 2, which was also re-investigated experimentally and computationally by Wagner in this study.…”

“…Such photorearrangements are following similar cascade steps as in the corresponding allcarbon triptycene derivative 2, which was also re-investigated experimentally and computationally by Wagner in this study. 4 The single other method to access a diborabenzouoranthene compound 7, which was recently described by Ji, Lin, Braunschweig and Marder, 7 is involving a relatively long thermally driven rearrangement of the ortho-phenyl bis-9-borauorene 6 at an elevated temperature (Scheme 4b). 7 Major impact in main-group chemistry and coordination chemistry is expected, since combining ditopic Lewis acids with ditopic Lewis bases will provide access to new inorganic polymers with alternating triptycene and Lewis base spacer.…”

“…7 Major impact in main-group chemistry and coordination chemistry is expected, since combining ditopic Lewis acids with ditopic Lewis bases will provide access to new inorganic polymers with alternating triptycene and Lewis base spacer. As diboratriptycene dianions are featuring a unique orientation of their aryl group, they act as chelating ligands toward M + ions via the p-electron clouds of the two 1,2-phenylene rings, 4 showcasing further use of these cage-shaped anionic di-boronate-triptycenes for the coordination of metallic cations.…”