Reinventing the De Mayo reaction: synthesis of 1,5-diketones or 1,5-ketoesters <i>via</i> visible light [2+2] cycloaddition of β-diketones or β-ketoesters with styrenes
作者:Rebeca Martinez-Haya、Leyre Marzo、Burkhard König
DOI:10.1039/c8cc07044j
日期:——
reaction between 1,3-diketones and styrenes following a [2+2] cycloaddition pathway via a photosensitization mechanism gives access to 1,5-diketones. The reaction has been applied to substituted styrenes and aryl- and alkyl-substituted ketones. Moreover, the method converts β-ketoesters, β-amido esters, and β-cyano ketones. Seven membered rings, a frequent structural motif of natural products, are also
Metal-Free Oxidative Radical Addition of Carbonyl Compounds to α,α-Diaryl Allylic Alcohols: Synthesis of Highly Functionalized Ketones
作者:Xue-Qiang Chu、Hua Meng、You Zi、Xiao-Ping Xu、Shun-Jun Ji
DOI:10.1002/chem.201404463
日期:2014.12.15
A metal‐free directalkylation of simple carbonyl compounds (ketones, esters, and amides) with α,α‐diaryl allylic alcohols is described. The protocol provides facile access to highly functionalized dicarbonyl ketones by a radical addition/1,2‐aryl migration cascade. The regioselectivity of the reaction was precisely controlled by the nature of the carbonyl compound.
Synthesis of a Tetraphenyl-Substituted Dihydropentalene and Its Alkali Metal Hydropentalenide and Pentalenide Complexes
作者:Stuart M. Boyt、Niko A. Jenek、Hugh J. Sanderson、Gabriele Kociok-Köhn、Ulrich Hintermair
DOI:10.1021/acs.organomet.1c00495
日期:2022.2.14
with a chalcone. Deprotonative metalation of 1,3,4,6-tetraphenyl-dihydropentalene with alkalimetal bases (Li, Na, K) of moderate basicity (pKa > 15) cleanly yields the corresponding hydropentalenide complexes, which exist as solvent-separated ion pairs in coordinating solvents such as THF, pyridine, and DMSO. A second deprotonative metalation with stronger alkalimetal bases (pKa > 25) yields the double-anionic
我们报告了基于环戊二烯与查耳酮的简单环化反应的 1,3,4,6-四苯基-二氢戊烯的高产液相合成。1,3,4,6-四苯基-二氢戊二烯与中等碱度 (p Ka > 15) 的碱金属碱 (Li, Na, K) 的去质子金属化干净地产生相应的氢戊二烯配合物,其以溶剂分离的离子对形式存在在 THF、吡啶和 DMSO 等配位溶剂中。使用更强的碱金属碱 (p Ka > 25) 进行第二次去质子化金属化产生双阴离子、10 π 芳族四苯基-戊二烯配合物,在 Li 2、Na 2和 K 2的情况下溶解度低. 在固态下,两种金属以反构型与每个阴离子环结合η 5 ,如在未取代的戊烯化物Li 2 [C 8 H 6 ]中。Li/Na/K 的混合金属四苯基-戊烯配合物显示出显着增强的溶解度,允许通过 NMR 和 UV-vis 光谱表征溶液相并应用于金属转移反应。
Metal-free [3 + 2 + 1] annulation of allylic alcohols, ketones, and ammonium acetate: radical-involving synthesis of 2,3-diarylpyridine derivatives
A three-component [3 + 2 + 1] annulation strategy for the synthesis of biologically and pharmaceutically active 2,3-diarylpyridine derivatives by using a series of allylic alcohols, ketones, and ammonium acetate as substrates has been developed. The method proceeds efficiently under metal-free conditions, and the desired heterocycles could be obtained in a site-specific selectivity manner with good
Photocycloaddition of Some Difluoro(aminoenonato)boron Complexes with Arylalkenes
作者:Kuniaki Itoh、Kazuhiko Okazaki、Yuan L. Chow
DOI:10.1002/hlca.200490027
日期:2004.2
The photocycloaddition of some difluoro[(methylamino-κN)alkenonato-κO]boron complexes 1 with arylalkenes 2 is discussed. The resulting [2+2] photoaddition gave the cyclobutane and azetidine derivatives (Schemes 1, 3, and 5). Rearrangements of the cyclobutane gave 1,5-diketones derivatives (Schemes 2, 4, and 5). The yields of the photoadducts were governed by the reduction and oxidation potentials.