To put to test the effect of 'Spectator metal-templated preorganization in organocatalysis' we have chosen a 2-guanidinobenzimidazole derivative (GBI  ) as a simple hydrogen bond donor. GBI is an effective ligand, and upon complexation to transition metal it becomes preorganized for several hydrogen bonding motifs. Upon preorganization, the rotational degrees of freedom that are intrinsic to the ligand are greatly reduced and both the reactivity and enantioselectivity are enhanced significantly.The generality of the catalytic behavior was established by extending the Michael addition reaction to various dicarbonyls and different nitroolefins. Exceeding the expectation, the 'spectator ruthenium-templated preorganized' catalyst showed good enantioselectivity even in the cases of notoriously infamous (in terms of enantioselectivity) alkyl nitroolefins.The above results are self-evident enough not only to coin the new term 'spectator metal' to the scientific community but also to combine 'organocatalysis' with 'metal-templated preorganization' to support the title. These new class of hybrid (organic-inorganic) hydrogen bond donors is unique and has excellent potential to start up a new branch of catalysis.

Spectator metal as a pre-organizing template in hydrogen-bond promoted enantioselective catalysis

247th National Meeting (2014)

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