Diruthenium Tetracarboxylate-Catalyzed Enantioselective Cyclopropanation with Aryldiazoacetates

Joshua K Sailer; Jack C Sharland; John Bacsa; Caleb F Harris; John F Berry; Djamaladdin G Musaev; Huw M L Davies

doi:10.1021/acs.organomet.3c00268

Diruthenium Tetracarboxylate-Catalyzed Enantioselective Cyclopropanation with Aryldiazoacetates

Organometallics. 2023 Jun 30;42(15):2122-2133. doi: 10.1021/acs.organomet.3c00268. eCollection 2023 Aug 14.

Authors

Joshua K Sailer¹, Jack C Sharland¹, John Bacsa¹, Caleb F Harris², John F Berry², Djamaladdin G Musaev^{1

3}, Huw M L Davies¹

Affiliations

¹ Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
² Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States.
³ Cherry L. Emerson Center for Scientific Computation, Emory University, 1521 Dickey Drive, Atlanta, Georgia 30322, United States.

Abstract

A series of chiral bowl-shaped diruthenium(II,III) tetracarboxylate catalysts were prepared and evaluated in asymmetric cyclopropanations with donor/acceptor carbenes derived from aryldiazoacetates. The diruthenium catalysts self-assembled to generate C₄-symmetric bowl-shaped structures in an analogous manner to their dirhodium counterparts. The optimum catalyst was found to be Ru₂(S-TPPTTL)₄·BAr^F [S-TPPTTL = (S)-2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate, BAr^F = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate], which resulted in the cyclopropanation of a range of substrates in up to 94% ee. Synthesis and evaluation of first-row transition-metal congeners [Cu(II/II) and Co(II/II)] invariably resulted in catalysts that afforded little to no asymmetric induction. Computational studies indicate that the carbene complexes of these dicopper and dicobalt complexes, unlike the dirhodium and diruthenium systems, are prone to the loss of carboxylate ligands, which would destroy the bowl-shaped structure critical for asymmetric induction.