Bifunctionality of dirhodium tetracarboxylates in metallaphotocatalysis

Abstract

Metallaphotocatalysis has been recognized as a pivotal catalysis enabling new reactivities. Traditional metallaphotocatalysis often requires two or more separate catalysts and exhibits flaw in cost and substrate-tolerance, thus representing an await-to-solve issue in catalysis. We herein realize metallaphotocatalysis with a bifunctional dirhodium tetracarboxylate ([Rh2]) alone. The [Rh2] shows an photocatalytic activity of promoting singlet oxygen (1O2) oxidation. By harnessing its photocatalytic activity, the [Rh2] catalyzes a photochemical cascade reaction (PCR) via combination of carbenoid chemistry and 1O2 chemistry. The PCR is characterized by high atom-efficiency, excellent stereoselectivities, mild conditions, scalable synthesis, and pharmaceutically interesting products. DFT calculations-aided mechanistic study rationalizes the reaction pathway and interprets the origin of stereoselectivities of the PCR. The products show inhibitory activity against PTP1B, being promising in the treatment of type II diabetes and cancers. Overall, here we show the bifunctional [Rh2] merges Rh-carbenoid chemistry and 1O2 chemistry.

Carbene-mediated stereoselective olefination of vinyl sulfoxonium ylides with diazo compounds and acetals

“…7 b , c Very recently, Hu's group developed trapping of a transient zwitterion intermediate, which is a source for 2-alkoxy furan with activated carbonyl compounds to generate vinylogous aldol adducts. 12 Based on our prior observation and Hu's report, we postulated that a similar kind of condensation between the transient zwitterion intermediate and activated aldehydes could lead to rubrolide analogs in a single step (Scheme 3a). However, our optimization studies (see the Page S5 in ESI†) reveal that the reaction affords the desired butenolide 5e in 82% yield using acetal instead of aldehyde under 3 mol% of [Ru( p -cymene)Cl 2 ] 2 and 30 mol% of TMSOTf in dichloroethane solvent.…”

Asymmetric Carbene‐Alkyne Metathesis‐Mediated Cascade: Synthesis of Benzoxazine Polychiral Polyheterocycles and Discovery of a Novel Pain Blocker

“…Our group has developed a series of multicomponent or cascade reactions based on the capture of highly reactive intermediates with electrophiles, [1][2][3] typically derived from carbene precursors like diazo compounds. However, the realization of this pathway via carbene-alkyne metathesis (CAM) [4][5][6][7][8][9][10][11][12] for polychiral polyheterocycles (PCPHCs) remains unexplored (Figure 1a).…”