Copper-Catalyzed Synthesis of Hindered Ethers from α-Bromo Carbonyl Compounds
作者:Zhe Zhou、Nicole Erin Behnke、László Kürti
DOI:10.1021/acs.orglett.8b02371
日期:2018.9.7
A catalytic method for the synthesis of sterically hindered ethers and thioethers from α-bromo carbonyl compounds and the corresponding nucleophiles using an inexpensive Cu(I) catalytic system is reported. This facile transformation takes place at ambient temperature and does not require the exclusion of air or moisture; thus, it is well-suited for the functionalization and derivatization of complex
Different Behaviors of a Cu Catalyst in Amine Solvents: Controlling N and O Reactivities of Amide
作者:Yu Yamane、Koichiro Miyazaki、Takashi Nishikata
DOI:10.1021/acscatal.6b02309
日期:2016.11.4
Controlling the reactivity of the nitrogen or oxygen nucleophile of an amide group to form C–N or C–O bonds by tuning reaction conditions is one of the most challenging issues in the use of amides in organic synthesis. Both nucleophiles in the amide group can individually participate in reactions, and most reactions employ a substrate-controlled methodology to achieve selectivity. However, in the reaction
Nucleophilic substitutions, including SN1 and SN2, are classical and reliable reactions, but a serious drawback is their intolerance for both bulky nucleophiles and chiral tertiary alkyl electrophiles for the synthesis of a chiral quaternary carbon center. An SRN1 reaction via a radical species is another conventional method used to carry out substitutionreactions of bulky nucleophiles and alkyl halides
包括S N 1和S N 2在内的亲核取代是经典且可靠的反应,但一个严重的缺点是它们对于庞大的亲核试剂和手性叔烷基亲电子试剂都不容忍合成手性季碳中心。一个S RN通过自由基物质进行的1反应是用于进行大体积亲核试剂和烷基卤化物的取代反应的另一种常规方法,但是不能使用手性叔烷基亲电试剂。因此,尚未充分研究使用手性叔烷基亲电试剂和大体积亲核试剂的立体特异性亲核取代反应。在本文中,我们描述了叔烷基醇与非手性或手性α-溴代羧酰胺作为叔烷基源的反应,以形成在氧原子上具有立体保留的两个不同叔烷基的拥挤醚化合物。
Copper-Catalyzed Functionalized Tertiary-Alkylative Sonogashira Type Couplings via Copper Acetylide at Room Temperature
作者:Yu Yamane、Naoki Miwa、Takashi Nishikata
DOI:10.1021/acscatal.7b02615
日期:2017.10.6
several reports on Sonogashira couplings, but most of the reported reactions have employed aryl or alkenyl halides as coupling partners. Therefore, Sonogashira coupling is unsuitable for alkyl loadings, especially tertiary alkyl groups. In this research, we found that a copper catalyst is effective for a reaction between a terminal alkyne and an α-bromocarbonyl compound to form a quaternary carbon having
Site-Selective Tertiary Alkyl-Fluorine Bond Formation from α-Bromoamides Using a Copper/CsF Catalyst System
作者:Takashi Nishikata、Syo Ishida、Ryo Fujimoto
DOI:10.1002/anie.201603426
日期:2016.8.16
A copper‐catalyzed site‐selective fluorination of α‐bromoamides possessing multiple reaction sites, such as primary and secondary alkyl−Br bonds, using inexpensive CsF is reported. Tertiary alkyl−F bonds, which are very difficult to synthesize, can be formed by this fluorination reaction with the aid of an amide group. Control experiments revealed that in situ generated CuF2 is a key fluorinating reagent