Palladacycle-Catalyzed Reaction of Bicyclic Alkenes with Terminal Ynones: Regiospecific Synthesis of Polysubstituted Furans
摘要:
A new synthetic strategy to access polysubstituted furans regiospecifically has been developed using simple bicyclic alkenes and terminal ynones as starting materials with palladacycles as unique active catalysts. A rational mechanism has also been proposed. This reaction features mild reaction conditions, easily available starting materials and palladacycle catalysts, a wide substrate scope, and high regiospecificity.
Substituted Pyrrololactams via Ring Expansion of Spiro-2<i>H</i>-pyrroles from Intermolecular Alkyne–Isocyanide Click Reactions
作者:Jimil George、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.6b03786
日期:2017.2.3
The facile synthesis of 6- to 8-membered pyrrololactams has been developed using a ringexpansion of spiro-2H-pyrroles, the products of intermolecular alkyne–isocyanide click reactions. The key to successful ringexpansion of spiro-2H-pyrroles to pyrrololactams is the enforced orbital overlap between the internal alkene and the amide carbonyl group through the conformationally locked bicyclic structures
Oxidation of Propargylic Alcohols with a 2-Quinoxalinol Salen Copper(II) Complex and<i>tert</i>-Butyl Hydroperoxide
作者:Kushan C. Weerasiri、Anne E. V. Gorden
DOI:10.1002/ejoc.201201394
日期:2013.3
selective oxidation of propargylic alcohols to yield the corresponding α,β-acetylenic carbonyl compounds when used in combination with the oxidant tert-butyl hydroperoxide (TBHP). Excellent yields (up to 99 %) are achieved for a variety of propargylic alcohols within 1 h of reaction time. The (salqu)copper(II) complex with TBHP can be used with propargylic alcohols that contain alkyl groups in the α-position
当与氧化剂叔丁基氢过氧化物 (TBHP) 结合使用时,2-喹喔啉醇 (salqu) 的铜 (II) 配合物是一种有效的催化剂,可用于选择性氧化炔丙醇以产生相应的 α,β-炔羰基化合物. 在 1 小时的反应时间内,各种炔丙醇的产率都很高(高达 99%)。与 TBHP 的 (salqu) 铜 (II) 配合物可与在 α 位含有烷基的炔丙醇一起使用,而炔丙醇很难用其他常用方法进行选择性氧化。通过使用这种催化方案,炔醇的氧化比分离的羟基、三键或炔丙基亚甲基的氧化也获得了优异的选择性。
Regioselective Synthesis of Pyrroles from Alkyne-Isocyanide Click Reactions: An Angle Strain-Induced Bond Migration Approach
作者:Jimil George、Hun Young Kim、Kyungsoo Oh
DOI:10.1002/adsc.201601017
日期:2016.12.7
direct regioselective synthesis of highly functionalized pyrroles with two different electron‐withdrawing groups has been developed using an angle strain‐induced 1,2‐shift of an electron‐withdrawing group in 2H‐pyrroles. The preferential migration aptitude of an electron‐withdrawing group over alkyl and aryl groups is believed to be the result of the orbital overlap between the internal alkene and the
Direct [3+2]-cycloaddition of electron-deficient alkynes with CF3CHN2: Regioselective one-pot synthesis of 3-trifluoromethylpyrazoles
作者:Feng Li、Jingjing Wang、Wenlong Pei、Hong Li、Huiling Zhang、Manman Song、Linyun Guo、Anan Zhang、Lantao Liu
DOI:10.1016/j.tetlet.2017.09.086
日期:2017.11
of electron-deficient terminal alkynes with 2,2,2-trifluorodiazoethane under mild conditions to afford a series of 5-substituted 3-trifluoromethylpyrazoles in highyields is described. The potential application of this cycloaddition reaction was demonstrated via the efficient synthesis of a key intermediate of the antiviral drug AS-136A and a fluorinated analog of Tebufenpyrad.
An efficient approach to access functionalized (2,3-dihydroisoxazol-4-yl) ketones has been developed by reacting nitrones 4 with ynones 7 or terminal ynones 10 in a one-pot fashion. The reaction went through a formal Sc(OTf)3-catalyzed [3 + 2]-cycloaddition process to generate a number of functionalized (2,3-dihydroisoxazol-4-yl) ketones 11aa–11aw, 11ba–11la and 12aa–12ae in moderate to good yields