Edwin Alfonzo

Journal article Journal of the American Chemical Society · October 2024 α-Amino esters are precursors to noncanonical amino acids used in developing small-molecule therapeutics, biologics, and tools in chemical biology. α-C-H amination of abundant and inexpensive carboxylic acid esters through nitrene transfer presents a direc ... Full text Cite

Stereospecific Enzymatic Conversion of Boronic Acids to Amines.

Journal article Journal of the American Chemical Society · July 2024 Boronic acids and esters are highly regarded for their safety, unique reactivity, and versatility in synthesizing a wide range of small molecules, bioconjugates, and materials. They are not exploited in biocatalytic synthesis, however, because enzymes that ... Full text Cite

Enzymatic Nitrogen Incorporation Using Hydroxylamine.

Journal article Journal of the American Chemical Society · September 2023 Hydroxylamine-derived reagents have enabled versatile nitrene transfer reactions for introducing nitrogen-containing functionalities in small-molecule catalysis, as well as biocatalysis. These reagents, however, result in a poor atom economy and stoichiome ... Full text Cite

Chemodivergent C(sp 3)–H and C(sp 2)–H cyanomethylation using engineered carbene transferases

Journal article Nature Catalysis · February 1, 2023 The ubiquity of C–H bonds presents an opportunity to efficiently elaborate and build complexity in organic molecules. Methods for selective functionalization, however, must differentiate among multiple, chemically similar C–H bonds: enzymes are attractive ... Full text Cite

New additions to the arsenal of biocatalysts for noncanonical amino acid synthesis

Journal article Current Opinion in Green and Sustainable Chemistry · December 1, 2022 Noncanonical amino acids (ncAAs) merge the conformational behavior and native interactions of proteinogenic amino acids with nonnative chemical motifs and have proven invaluable in developing modern therapeutics. This blending of native and nonnative chara ... Full text Cite

Enzymatic Nitrogen Insertion into Unactivated C-H Bonds.

Journal article Journal of the American Chemical Society · October 2022 Selective functionalization of aliphatic C-H bonds, ubiquitous in molecular structures, could allow ready access to diverse chemical products. While enzymatic oxygenation of C-H bonds is well established, the analogous enzymatic nitrogen functionalization ... Full text Cite

α-Heteroarylation of Thioethers via Photoredox and Weak Brønsted Base Catalysis.

Journal article Organic letters · August 2021 We report the C-H activation of thioethers to α-thio alkyl radicals and their addition to N-methoxyheteroarenium salts for the redox-neutral synthesis of α-heteroaromatic thioethers. Studies are consistent with a two-step activation mechanism, where ... Full text Cite

Photoredox and weak Brønsted base dual catalysis: Alkylation of α-thio alkyl radicals

Journal article ACS Catalysis · November 6, 2020 We report the C−H activation of thioethers to α-thio alkyl radicals and their addition to electron-deficient olefins to afford alkylated products through dual photoredox and weak Brønsted base catalysis. Mechanistic studies are consistent with a two-step a ... Full text Cite

Photoredox Generated Carbonyl Ylides Enable a Modular Approach to Aryltetralin, Dihydronaphthalene, and Arylnaphthalene Lignans.

Journal article Organic letters · August 2020 A one-pot synthesis of dihydronaphthalenes and arylnaphthalenes from epoxides and common dipolarophiles is described. The reaction proceeds through photoredox activation of epoxides to carbonyl ylides, which undergo concerted [3 + 2] dipolar cycloaddition ... Full text Cite

A sterically encumbered photoredox catalyst enables the unified synthesis of the classical lignan family of natural products

Journal article Chemical Science · January 1, 2019 Herein, we detail a unified synthetic approach to the classical lignan family of natural products that hinges on divergence from a common intermediate that was strategically identified from nature's biosynthetic blueprints. Efforts toward accessing the com ... Full text Cite

One-pot synthesis of epoxides from benzyl alcohols and aldehydes

Journal article Beilstein Journal of Organic Chemistry · September 3, 2018 A one-pot synthesis of epoxides from commercially available benzyl alcohols and aldehydes is described. The reaction proceeds through in situ generation of sulfonium salts from benzyl alcohols and their subsequent deprotonation for use in Corey–Chaykovsky ... Full text Cite

Redesign of a Pyrylium Photoredox Catalyst and Its Application to the Generation of Carbonyl Ylides.

Journal article Organic letters · June 2017 We report the exploration into photoredox generation of carbonyl ylides from benzylic epoxides using newly designed 4-mesityl-2,6-diphenylpyrylium tetrafluoroborate (MDPT) and 4-mesityl-2,6-di-p-tolylpyrylium tetrafluoroborate (MD(p-tolyl)PT) catalysts. Th ... Full text Cite