4 research outputs found
Adaptation of a Small-Molecule Hydrogen-Bond Donor Catalyst to an Enantioselective Hetero-DielsâAlder Reaction Hypothesized for Brevianamide Biosynthesis
Chiral diamine-derived hydrogen-bond
donors were evaluated for
their ability to effect stereocontrol in an intramolecular hetero-DielsâAlder
(HDA) reaction hypothesized in the biosynthesis of brevianamides A
and B. Collectively, these results provide proof of principle that
small-molecule hydrogen-bond catalysis, if even based on a hypothetical
biosynthesis construct, holds significant potential within enantioselective
natural product synthesis
1,4-Dihydropyridines as Alkyl Radical Precursors: Introducing the Aldehyde Feedstock to Nickel/Photoredox Dual Catalysis
A Ni/photoredox dual catalytic cross-coupling
is disclosed in which
a diverse range of (hetero)Âaryl bromides are used as electrophiles,
with 1,4-dihydropyridines serving as precursors to C<sub>sp</sub><sup>3</sup>-centered alkyl radical coupling partners. The reported method
is characterized by its extremely mild reaction conditions, enabling
access to underexplored cores
Adaptation of a Small-Molecule Hydrogen-Bond Donor Catalyst to an Enantioselective Hetero-DielsâAlder Reaction Hypothesized for Brevianamide Biosynthesis
Chiral diamine-derived hydrogen-bond
donors were evaluated for
their ability to effect stereocontrol in an intramolecular hetero-DielsâAlder
(HDA) reaction hypothesized in the biosynthesis of brevianamides A
and B. Collectively, these results provide proof of principle that
small-molecule hydrogen-bond catalysis, if even based on a hypothetical
biosynthesis construct, holds significant potential within enantioselective
natural product synthesis
Enantioselective Small Molecule Synthesis by Carbon Dioxide Fixation using a Dual Brønsted Acid/Base Organocatalyst
Carbon
dioxide exhibits many of the qualities of an ideal reagent: it is
nontoxic, plentiful, and inexpensive. Unlike other gaseous reagents,
however, it has found limited use in enantioselective synthesis. Moreover,
unprecedented is a tool that merges one of the simplest biological
approaches to catalysisî¸Brønsted acid/base activationî¸with
this abundant reagent. We describe a metal-free small molecule catalyst
that achieves the three component reaction between a homoallylic alcohol,
carbon dioxide, and an electrophilic source of iodine. Cyclic carbonates
are formed enantioselectively