Synthesis of Sterically Hindered α-Hydroxycarbonyls through Radical–Radical Coupling
作者:Kenji Ota、Kazunori Nagao、Hirohisa Ohmiya
DOI:10.1021/acs.orglett.1c01358
日期:2021.6.4
describe a synthetic approach to sterically hindered α-hydroxy carbonyl compounds through radical–radical coupling. An organic photoredox catalysis reaction converts an aliphatic carboxylic acid and α-ketocarbonyl to a transient alkyl radical and a persistent ketyl radical, respectively, which couple selectively based on the persistent radical effect. This protocol allows the use of primary, secondary, and
Site-Directed Asymmetric Quaternization of a Peptide Backbone at a C-Terminal Azlactone
作者:Daisuke Uraguchi、Yoshihiro Asai、Takashi Ooi
DOI:10.1002/anie.200803661
日期:2009.1.12
Dual‐purpose activation: Peptide C‐terminal azlactones I undergo stereoselective alkylation with high efficiency by the use of a newly devised chiral tetraaminophosphonium salt as a phase‐transfer catalyst, and the alkylated azlactone products II can be employed directly for peptide ligation (see scheme, LG=leaving group). In this way, a wide range of chiral quaternary α‐amino acid residues can be
Characterization of a methoxylated oxazol-5-one derivative : an unexpected by-product in a dehydropeptide synthesis
作者:Alvin C. Bach、Alysia A. Baldwin、Lila M. Gierasch、Arnold L. Rheingold
DOI:10.1039/c39830001398
日期:——
During the synthesis of the oxazol-5-onederivative (2) of t-butoxycarbonyl-glycyl-2,3-didehydrophenylalanine, the unexpected side product the 2-methoxyoxazol-5-one (3) was isolated and subsequently characterized by n.m.r., i.r., and single-crystal X-ray diffraction analysis.