Isothiourea‐Catalyzed Acylative Kinetic Resolution of Tertiary α‐Hydroxy Esters
作者:Shen Qu、Samuel M. Smith、Víctor Laina‐Martín、Rifahath M. Neyyappadath、Mark D. Greenhalgh、Andrew D. Smith
DOI:10.1002/anie.202004354
日期:2020.9.14
acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiarycarbinol centre. For more sterically congested alcohols
2-Amino-5,6-difluorophenyl-1<i>H</i>-pyrazole-Directed Pd<sup>II</sup> Catalysis: Arylation of Unactivated β-C(sp<sup>3</sup>)–H Bonds
作者:Jinyue Yang、Xiaopan Fu、Shibiao Tang、Kezuan Deng、Lili Zhang、Xianjin Yang、Yafei Ji
DOI:10.1021/acs.joc.9b01276
日期:2019.8.16
efficient and readily removable directing group. Two fluoro groups are installed at the 5- and 6-position of the anilino moiety in 2-aminophenyl-1H-pyrazole, clearly enhancing the directing ability of the auxiliary. In addition, the protocol employs Cu(OAc)2/Ag3PO4 (1.2/0.3) as additives, evidently reducing the stoichiometric amount of expensive silversalts. Furthermore, this process exhibits high β-site
首次描述了使用2-氨基-5,6-二氟苯基-1 H-吡唑作为有效且易于去除的钯衍生物催化羧酸衍生物中未活化的β-C(sp 3)–H键与芳基碘化物的芳基化指导小组。在2-氨基苯基-1 H-吡唑的苯胺基部分的5-位和6-位安装了两个氟基团,明显增强了辅助剂的导向能力。此外,该协议使用Cu(OAc)2 / Ag 3 PO 4(1.2 / 0.3)作为添加剂,明显减少了昂贵的银盐的化学计量。此外,该方法显示出高的β-位点选择性,与含有α-氢原子的各种底物的相容性以及优异的官能团耐受性。
Novel Annulation Reactions of Aryl Methyl Ketenes with Zwitterions Derived from Dimethyl Acetylenedicarboxylate and <i>N</i>-Alkylimidazoles
作者:Cheng Ma、Hanfeng Ding、Yanguang Wang
DOI:10.1021/ol061126p
日期:2006.7.1
[reaction: see text] A novel three-component annulation reaction involving N-alkylimidazoles, dimethyl acetylenedicarboxylate, and in situ generated aryl methyl ketenes leading to the synthesis of 6-vinyl-1,3a-diazapentalene derivatives is reported.
Aza-oxindole synthesis by oxidative coupling of Csp2–H and Csp3–H centers
作者:Chandan Dey、E. Peter Kündig
DOI:10.1039/c2cc17871k
日期:——
A Cu(II) mediated oxidative Csp2âH and Csp3âH coupling protocol gives access to aza-oxindoles in good to excellent yield in the presence of NaOtBu as base and toluene as solvent.
An investigation into the electrophilic cyclisation of N-acyl-pyrrolidinium ions: a facile synthesis of pyrrolo-tetrahydroisoquinolones and pyrrolo-benzazepinones
作者:Frank D. King、Abil E. Aliev、Stephen Caddick、Royston C. B. Copley
DOI:10.1039/b907400g
日期:——
N-arylethyl-acylpyrrolidinium ions gave moderate to good yields of pyrrolo-tetrahydroisoquinolones and pyrrolo-benzazepinones respectively. Electron-donating R substituents enhanced the rate of reaction and gave higher yields than electron-withdrawing substituents. Substituents on the methyl or ethyl chain in general enhanced the reaction, unless sterically encumbered. The equivalent acylpiperidinium ions cyclised much