Substituted γ and δ-ketoaldehydes may be conveniently synthesized in two steps from imine carbanions, which are obtained by reaction with hyperbasic media. These anions are stable at low temperature (−30°); they react with functional electrophiles to afford masked ketoaldehydes which may be cyclised into various cyclopentenones or cyclohexenones.
Visible-Light Photocatalytic Preparation of 1,4-Ketoaldehydes and 1,4-Diketones from α-Bromoketones and Alkyl Enol Ethers
作者:William H. García-Santos、Jeferson B. Mateus-Ruiz、Alejandro Cordero-Vargas
DOI:10.1021/acs.orglett.9b01275
日期:2019.6.7
A Ru2+-photocatalyzed, visible-light-mediated ATRA reaction for the straightforward preparation of 1,4-ketoaldehydes, 1,4-diketones, and 1,4-ketoesters, which are of difficult access by other means, is reported herein. This method employs readily accessible α-bromoketones and alkyl vinyl ethers as starting materials, allowing the construction of secondary, tertiary, and challenging quaternary centers
There is provided a compound exhibiting an activity of suppressing immune response with reduced adverse drug reactions, which compound is useful in the chemotherapy for preventing or treating, for example, a wide range of various autoimmune diseases including systemic erythematodes, chronic rheumatoid arthritis, Type I diabetes, inflammatory bowel disease, biliary cirrhosis, uveitis, multiple sclerosis or other disorders, or chronic inflammatory diseases, or cancers, lymphoma or leukemia, or resistance to organ or tissue transplantation or rejection against transplantation.
Novel amine compounds having an S1P1/Edg1 receptor agonist effect, possible stereoisomers or racemic bodies of the compounds, or pharmacologically acceptable salts, hydrates or solvates of the compound, the stereoisomers or the racemic bodies, or prodrugs of the compounds, the stereoisomers, the racemic bodies, the salts, the hydrates or the solvates, are provided.
Dibromo-BODIPY as an Organic Photocatalyst for Radical–Ionic Sequences
作者:William H. García-Santos、Javier Ordóñez-Hernández、Mónica Farfán-Paredes、Hiram M. Castro-Cruz、Norma A. Macías-Ruvalcaba、Norberto Farfán、Alejandro Cordero-Vargas
DOI:10.1021/acs.joc.1c01598
日期:2021.12.3
A new dibrominated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) is reported as a new metal-free photocatalyst. This BODIPY showed similar optoelectronic, electrochemical, and performance properties to those of Ru(bpy)3Cl2, one of the most common photocatalysts in a known radical–ionic transformation, such as the formation of 1,4-dicarbonyl compounds. Moreover, additional sequences in which the
Atroposelective Synthesis of Axially Chiral N‐Arylpyrroles by Chiral‐at‐Rhodium Catalysis
作者:Chen‐Xi Ye、Shuming Chen、Feng Han、Xiulan Xie、Sergei Ivlev、K. N. Houk、Eric Meggers
DOI:10.1002/anie.202004799
日期:2020.8.3
Specifically, N‐arylpyrroles were alkylated with N‐acryloyl‐1H‐pyrazole electrophiles in up to 93 % yield and with up to >99.5 % ee , and follow‐up conversions reveal the synthetic utility of this new method. DFT calculations elucidate the origins of the observed excellent atroposelectivity.