Metal-Free Iodosulfonylation of Internal Alkynes: Stereodefined Access to Tetrasubstituted Olefins
作者:Ravi Kumar、Vikas Dwivedi、Maddi Sridhar Reddy
DOI:10.1002/adsc.201700576
日期:2017.8.17
The stereoselective E‐iodosulfonylation of internalalkynes for synthesizing highly defined tetrasubstituted olefins using sodium phenyl sulfinate and iodine has been achieved. Most of the alkynes explored are non‐symmetrical and the regioselection is under full control. Arylalkynes with various electron‐withdrawing groups like keto, aldehyde, ester, amide, cyano, sulfone, bromo, chloro and iodo on
A variety of functionalities, including the whole range of halogen substituents, are tolerated in the title reaction, an intramolecular approach for the construction of a multisubstituted indole skeleton from readily available enaminones (see scheme; phen=1,10‐phenanthroline). The indole products are also prepared directly in high yield from α,β‐ynones and primary amines.
An effective phosphine-catalyzed protocol has been established for the syntheses of 1,3-diketones and nitriles from alkynones with oximes as hydroxide surrogates. This method features the use of a phosphine catalyst, compatibility with various functional groups and ambient temperature, which makes this approach very practical. A plausible mechanism was proposed.
Base-Controlled Divergent Synthesis of 5-Cyanobenzoxepines and Benzofuro[2,3-<i>b</i>]pyridines from 2-Bromophenylacetonitriles and Ynones
作者:Lu-Lu Chen、Jing-Wen Zhang、Pei Chen、Shuai Zhang、Wan-Wan Yang、Ji-Ya Fu、Jun-Yan Zhu、Yan-Bo Wang
DOI:10.1021/acs.orglett.9b01700
日期:2019.7.19
2-bromophenylacetonitriles and ynones has been developed. Various functionalized 5-cyanobenzoxepines and benzofuro[2,3-b]pyridines were obtained with a broad substrate scope and high regioselectivity in moderate to excellent yield. Of importance, an unexpected O-rearrangement reaction to access benzofuro[2,3-b]pyridines was observed using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the base, and the possible mechanism
已经开发出一种有效的碱控制的2-溴苯基乙腈和炔酮的发散环化反应。获得了各种官能化的5-氰基苯并pine庚因和苯并呋喃[2,3- b ]吡啶,它们具有较宽的底物范围和较高的区域选择性,且产率中等至优异。重要的是,使用1,8-二氮杂双环[5.4.0]十一碳-7-烯(DBU)作为碱,观察到了意外的O重排反应,可接近苯并呋喃[2,3- b ]吡啶。由18个O标记的实验支持。另外,研究了克级合成和产物的进一步转化。
Electrochemical Palladium-Catalyzed Oxidative Sonogashira Carbonylation of Arylhydrazines and Alkynes to Ynones
作者:Yong Wu、Li Zeng、Haoran Li、Yue Cao、Jingcheng Hu、Minghao Xu、Renyi Shi、Hong Yi、Aiwen Lei
DOI:10.1021/jacs.1c06036
日期:2021.8.18
palladium-catalyzed oxidative carbonylation of arylhydrazines with alkynes, which is regarded as an alternative supplement of the carbonylative Sonogashira reaction. Combining an undivided cell with constant current mode, oxygen-free conditions avoids the explosion hazard of CO. A diversity of ynones are efficiently obtained using accessible arylhydrazines and alkynes under copper-free conditions. A possible mechanism
使用一氧化碳的氧化羰基化已发展成为对有价值的含羰基化合物有吸引力的工具,而将 CO 与化学计量量的化学氧化剂(尤其是氧气)混合是危险的,并限制了其在放大合成中的应用。通过采用阳极氧化,我们开发了一种电化学钯催化的芳基肼与炔烃的氧化羰基化,被认为是羰基化 Sonogashira 反应的替代补充。将未分割的电池与恒流模式相结合,无氧条件避免了 CO 的爆炸危险。在无铜条件下使用可接近的芳基肼和炔烃可以有效地获得多种炔酮。基于循环伏安法,电化学 Pd(0)/Pd(II) 循环的可能机制被合理化,