The first, oxidative photocatalytic method for phenol-phenol homo-coupling and cross-coupling is described and isolated yields of up to 97% are obtained. Measured oxidation potentials and computed nucleophilicity parameters are consistent with a nucleophilic attack of one partner onto the oxidized radical form of the other partner. Understanding of this model permitted development of cross-coupling reactions between nucleophilic phenols/arenes and easily oxidized phenols in high selectivity and efficiency. A highlight of this method is that one equivalent of each coupling partner is utilized. Building on these findings, the first non-enzymatic, catalytic method for coupling tyrosine was developed. ASSOCIATED CONTENT Supporting Information. The Supporting Information is available free of charge on the ACS Publications website. Experimental protocols and spectroscopic data (pdf).

A mild and efficient method for the vanadium-catalyzed intramolecular coupling of tethered free phenols is described. The corresponding phenol-dienone products are prepared directly in good yields with low catalyst loadings. Electronically diverse tethered phenol precursors are well tolerated, and the catalytic method was effectively applied as the key step in syntheses of three natural products and a synthetically useful morphinan alkaloid precursor.

The first, oxidative photocatalytic method for phenol-phenol homo-coupling and cross-coupling is described and isolated yields of up to 97% are obtained. Measured oxidation potentials and computed nucleophilicity parameters are consistent with a nucleophilic attack of one partner onto the oxidized radical form of the other partner. Understanding of this model permitted development of cross-coupling reactions between nucleophilic phenols/arenes and easily oxidized phenols in high selectivity and efficiency. A highlight of this method is that one equivalent of each coupling partner is utilized. Building on these findings, the first non-enzymatic, catalytic method for coupling tyrosine was developed.

A concise synthesis of protected 5-cyano-L-tryptophan (Trp5CN) has been developed for 2D IR spectroscopic investigations within peptides or proteins. To assess the potential of differently substituted cyano-tryptophans, several model cyanoindole systems were characterized using IR spectroscopy. Upon assessment of their spectroscopic properties, Trp5CN was integrated into a model peptide sequence, Trp5CN–Gly–Phe4CN, to elucidate its structure. This peptide demonstrates the capability of this probe, Trp5CN and Phe4CN, to capture structural information via 2D IR spectroscopy. The 2D IR spectrum of the peptide in water was simulated to reveal a unique spectral signature resulting from the presence of dipolar coupling. The coupling strength between cyano-labels was determined to be 1.4 cm−1 by matching the slopes along the max contour between the simulated and experimental spectrum. Using transition dipole coupling, a distance between the two probes of 13 Å was calculated.

The electrochemical oxidation of sensitive propargylic benzylic alcohols having varying substituents is reported. We describe the preparation and characterization of N-hydroxytetrafluorophthalimide (TFNHPI) and pseudo-high-throughput development of a green electrochemical oxidation protocol for sensitive propargylic benzylic alcohols that employs TFNHPI as a stable electrochemical mediator. The electrochemical oxidation of propargylic benzylic alcohols was leveraged to develop short synthetic pathways for preparing gram quantities of resveratrol natural products such as pauciflorols.