Mono‐, bis‐ and tris‐piperidine fused imidazolinium salts: their in situ catalytic applications for CC bond formation in aqueous solutions

Abstract

The 1,5,6,7,8,8a-hexahydroimidazo[1,5-a]pyridine, 3, was quaternized with 2-(bromomethyl-1,3,5-trimethylbenzene, 1,4-bis(bromomethyl)-2,3,5,6-tetramethylbenzene, 2,4-bis(bromomethyl)-1,3,5-trimethylbenzene, 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene and 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene to obtain mono-, bis-and tris-imidazolinium salts (4-7) which were characterized by elemental analysis and NMR spectroscopy. In order to understand the effects of these changes on the N-substituent and how they translate to catalytic activity, these new salts (4-7) with Pd(OAc) 2 were applied as in situ catalysts for Suzuki-Miyaura and Heck-Mirozoki cross-coupling reactions of aryl chlorides and aryl bromides, respectively. The tris-imidazolinium salts (7) were found to be more efficient than the related analogs 4-6.

Phosphorescent Cyclometalated Platinum(ii) Hexahydroimidazo[1,5‐a]pyridinylidene Complexes

“…In particular, only a few examples of complexes with cyclometalated NHCs are known [45–47] . The saturated derivative of the imidazo[1,5‐ a ]pyridine framework (Scheme 1) is known as a NHC motif for over a decade and can be found in iridium, palladium and rhodium complexes [48–58] . But to the best of our knowledge there are neither platinum nor cyclometalated complexes known with this motif.…”

Substrate-Controlled Chemoselective Reactions of Isocyanoacetates with Amides and Lactams

“…The latter have potential antimicrobial 14 and human histamine H4 receptor antagonistic activities 13 and have been used as catalysts in catalytic hydrogenation 12b and the C−C cross-coupling reactions. 15 Very few methods have been reported for their synthesis. Thus, developing other electrophilic partners such as amides in the above-mentioned reactions would extend the scope of those reactions and provide a direct access to bicyclic imidazoline derivatives.…”

“… , Despite these progresses, the electrophilic partners in those reactions are limited to preformed and in situ-generated imines except for two cases where N , N -dimethylformamide dimethylacetal and a carbonitrile have been used in the condensations with diamines to give bicyclic imidazoline derivatives. The latter have potential antimicrobial and human histamine H4 receptor antagonistic activities and have been used as catalysts in catalytic hydrogenation and the C–C cross-coupling reactions . Very few methods have been reported for their synthesis.…”