Enantioselective Biomimetic Cyclization of Isoprenoids Using Lewis Acid-Assisted Chiral Brønsted Acids: Abnormal Claisen Rearrangements and Successive Cyclizations
have been achieved by several groups; however, no general “biomimetic” method has yet been reported. In this paper we describe the biomimeticcyclization of simple isoprenoids to polycyclic isoprenoids using Lewis acid-assisted chiral Bronsted acids, “chiral LBAs”. This is the first example of a proton-induced enantioselective ene cyclization in synthetic chemistry. Geranyl phenyl ethers, o-geranylphenols
Metal-Free C–O Bond Functionalization: Catalytic Intramolecular and Intermolecular Benzylation of Arenes
作者:Luis Bering、Kirujan Jeyakumar、Andrey P. Antonchick
DOI:10.1021/acs.orglett.8b01495
日期:2018.7.6
conditions enabled a catalytic and metal-free Friedel–Craftsalkylation reaction with benzylic alcohols, producing water as the stoichiometric byproduct. A comprehensive scope (>50 examples) for both approaches and application in drug synthesis were demonstrated. Mechanistic studies suggest a Lewis acid-based mechanism for the metal-free Friedel–Crafts reaction.
Geiparvarin Analogs. 3. Synthesis and cytostatic activity of 3(2H)-furanone and 4,5-dihydro-3(2H)-furanone congeners of geiparvarin, containing a geraniol-like fragment in the side chain.
作者:Pier G. Baraldi、Stefano Manfredini、Daniele Simoni、Mojgan Aghazadeh Tabrizi、Jan Balzarini、Erik De Clercq
DOI:10.1021/jm00088a025
日期:1992.5
region of the olefinic double bond by introduction of the characteristic alkenyl side chain of ascofuranone (compounds 10a-f and 11a-f) markedly decreased the cytostatic activity as compared to geiparvarin itself, but this effect does not seem to be correlated to the presence of the furanone moiety linked to the alkenyl chain or to the ability to afford Michael type adducts. Replacement of the coumarin