Photoredox-Catalyzed Multicomponent Petasis Reaction with Alkyltrifluoroborates

Abstract

A redox-neutral alkyl Petasis reaction has been developed that proceeds via photoredox catalysis. A diverse set of primary, secondary, and tertiary alkyltrifluoroborates participate effectively in this reaction through a single-electron transfer mechanism, in contrast to the traditional two-electron Petasis reaction, which accommodates only unsaturated boronic acids. This protocol is ideal to diversify benzyl-type and glyoxalate-derived aldehydes, anilines, and alkyltrifluoroborates toward the rapid assembly of libraries of higher molecular complexity important in pharmaceutical and agrochemical settings.

A general N-alkylation platform via copper metallaphotoredox and silyl radical activation of alkyl halides

“…When adding the persistent radical 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) to the standard bromocyclohexane coupling reaction, product 1 was not detected, and the major species observed from bromocyclohexane conversion was TEMPO-trapped adduct 65 (Figure 7). Given that adduct 65 is well-established to be forged via radicalradical coupling of TEMPO with the transient cyclohexyl radical, 82 these results, in tandem with ring-opening studies and control experiments (Figures 1, 7, and S22-S25), denote the anticipated open-shell pathways needed to enable HARC-type coupling. .…”

Synthesis of Chiral Amines by C–C Bond Formation with Photoredox Catalysis

“…The Molander group further expanded this chemistry to include a three-component synthesis with a tandem imine condensation/radical addition process (Scheme 40c). 84 This Ir-catalyzed three-component reaction was employed with a very wide scope of aryl substituents and radical precursors to afford adducts 4.16, of which only a small selection are illustrated here. Functionalization of indomethacin by this method led to 4.17b, and a precursor of glucagon receptor modulator was assembled using this three-component coupling, illustrating its practical potential.…”

Visible‐Light Driven Organo‐photocatalyzed Multicomponent Reaction for C(sp3)−H Alkylation of Phosphoramides with in situ Generated Michael Acceptors

“…reported Ugi MCRs to synthesize α ‐amino amides and imides from tertiary amines (Scheme 1a) [5a] . Simultaneously, Molander's group developed a multi‐component Petasis reaction that used alkyl trifluoroborates as a radical precursor (Scheme 1b) [5b] . Opatz's et al .…”