Electrophotochemical Ce-Catalyzed Ring-Opening Functionalization of Cycloalkanols under Redox-Neutral Conditions: Scope and Mechanism
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2022; 144 (30): 13895-13902
Selective cleavage and functionalization of C-C bonds in alcohols is gaining increasing interest in organic synthesis and biomass conversion. In particular, the development of redox-neutral catalytic methods with cheap catalysts and clean energy is of utmost interest. In this work, we report a versatile redox-neutral method for the ring-opening functionalization of cycloalkanols by electrophotochemical (EPC) cerium (Ce) catalysis. The EPC-Ce-enabled catalysis allows for cycloalkanols with different ring sizes to be cleaved while tolerating a broad range of functional groups. Notably, in the presence of chloride as a counteranion and electrolyte, this protocol selectively leads to the formation of C-CN, C-C, C-S, or C-oxime bonds instead of a C-halide bond after β-scission. A preliminary mechanistic investigation indicates that the redox-active Ce catalyst can be tuned by electro-oxidation and photo-reduction, thus avoiding the use of an external oxidant. Spectroscopic characterizations (cyclic voltammetry, UV-vis, electron paramagnetic resonance, and X-ray absorption fine structure) suggest a Ce(III)/Ce(IV) catalytic pathway for this transformation, in which a Ce(IV)-alkoxide is involved.
View details for DOI 10.1021/jacs.2c05520
View details for Web of Science ID 000832335900001
View details for PubMedID 35861667
- Site-selective amination towards tertiary aliphatic allylamines NATURE CATALYSIS 2022; 5 (7): 642-651
Scalable and selective deuteration of (hetero) arenes
2022; 14 (3): 334-+
Isotope labelling, particularly deuteration, is an important tool for the development of new drugs, specifically for identification and quantification of metabolites. For this purpose, many efficient methodologies have been developed that allow for the small-scale synthesis of selectively deuterated compounds. Due to the development of deuterated compounds as active drug ingredients, there is a growing interest in scalable methods for deuteration. The development of methodologies for large-scale deuterium labelling in industrial settings requires technologies that are reliable, robust and scalable. Here we show that a nanostructured iron catalyst, prepared by combining cellulose with abundant iron salts, permits the selective deuteration of (hetero)arenes including anilines, phenols, indoles and other heterocycles, using inexpensive D2O under hydrogen pressure. This methodology represents an easily scalable deuteration (demonstrated by the synthesis of deuterium-containing products on the kilogram scale) and the air- and water-stable catalyst enables efficient labelling in a straightforward manner with high quality control.
View details for DOI 10.1038/s41557-021-00846-4
View details for Web of Science ID 000742249800001
View details for PubMedID 35027706
View details for PubMedCentralID PMC8898765
- Electrochemical Cobalt-catalyzed Cyclotrimerization of Alkynes to 1,2,4-Substituted Arenes ACS CATALYSIS 2021; 11 (24): 14892-14897
Electrochemical Oxidation Enables Regioselective and Scalable alpha-C(sp(3))-H Acyloxylation of Sulfides
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2021; 143 (9): 3628-3637
A highly selective, environmentally friendly, and scalable electrochemical protocol for the construction of α-acyloxy sulfides, through the synergistic effect of self-assembly-induced C(sp3)-H/O-H cross-coupling, is reported. It features exceptionally broad substrate scope, high regioselectivity, gram-scale synthesis, construction of complex molecules, and applicability to a variety of nucleophiles. Moreover, the soft X-ray absorption technique and a series of control experiments have been utilized to demonstrate the pivotal role of the self-assembly of the substrates, which indeed is responsible for the excellent compatibility and precise control of high regioselectivity in our electrochemical protocol.
View details for DOI 10.1021/jacs.1c00288
View details for Web of Science ID 000629075900039
View details for PubMedID 33635055
- Intermetallic Compounds as an Alternative to Single-atom Alloy Catalysts: Geometric and Electronic Structures from Advanced X-ray Spectroscopies and Computational Studies CHEMCATCHEM 2020; 12 (5): 1325-1333