Practical Synthesis of
<i>α</i>
‐Trifluoromethylated Pyridines Based on Regioselective Cobalt‐Catalyzed [2+2+2] Cycloaddition using Trifluoromethylated Diynes with Nitriles
作者:Tatsuya Kumon、Shigeyuki Yamada、Tomohiro Agou、Hiroki Fukumoto、Toshio Kubota、Gerald B. Hammond、Tsutomu Konno
DOI:10.1002/adsc.202001433
日期:2021.3.29
Regioselective cobalt‐catalyzed [2+2+2] cycloaddition using fluorine‐containing diynes with nitriles was described. Cycloaddition of fluorinated diynes with nitriles under the influence of CoCl2(phen), zinc bromide, and zinc dust in dichloroethane at 80 °C for 3 h took place smoothly, exclusively affording the corresponding α‐fluoroalkylated pyridines in excellent yields. In addition, dinitriles as
描述了使用含氟二炔与腈进行区域选择性钴催化的[2+2+2]环加成反应。在 CoCl 2 (phen)、溴化锌和锌粉的影响下,氟化二炔与腈在二氯乙烷中在 80 °C 下环加成 3 小时,顺利进行,以优异的收率专门提供了相应的α-氟烷基化吡啶。此外,二腈作为底物也被发现适合该反应,以优异的收率得到相应的氟烷基化联吡啶衍生物。
Facile conversion of CF3-containing propargylic alcohol derivatives via the corresponding allenes
Empirical information on the acidity of the propargylic proton from our previous work allowed us to develop novel synthetic transformations of readily available terminally trifluoromethylated propargylic alcohols 1 into the corresponding allenyl tosylates 3a, 1-tosyloxy- or 1-acyloxy-4,4,4-trifluorobutan-2-ones 4, and 2-(2,2,2-trifluoroethyl)prop-2-en-1-ones 5, which was enabled by such common bases
Treatment of various fluorinated internal alkynes with 10 mol% of RhCl3·H2O and 30 mol% of i-Pr2NEt in toluene at the reflux temperature for 18 h gave the corresponding trimerization products as an isomeric mixture in high yields. Cycloaddition using 1.0 equiv. of fluorinated alkynes and 2.0 equiv. of non-fluorinated alkynes under the same reaction conditions as in the trimerization led to mono- and
A novel method for the generation of 3,3,3-trifluoro-propynyllithium is reported, which involves treatment of trifluoromethyl-substituted enol tosylate, prepared from 1,1-dichloro-3,3,3-trifluoroacetone, with two equivalents of butyllithium. -Palladium-catalyzed coupling reaction of sulfonates of the carbonyl adducts with organozinc reagents gave trifluoromethyl-containing tri- and tetrasubstituted
Intermolecular Pauson–Khand reaction of fluoroalkylated alkynes with 2-norbornene or 2,5-norbornadiene at the reflux temperature of dichloroethane proceeded smoothly to give the corresponding cyclopentenone derivatives in high yields as a mixture of regioisomers. On the other hand, intramolecular Pauson–Khand reaction of fluorine-containing 1,6-enyne proceeded in the presence of NMO or TMANO to give