Synthesis of ortho-Haloaminoarenes by Aryne Insertion of Nitrogen–Halide Bonds
摘要:
A rapid and general access to ortho-haloaminoarenes has been developed by aryne insertion into N-chloramine, N-bromoamine, and N-iodoamine bonds via two complementary protocols harnessing fluoride-promoted 1,2-elimination of ortho-trimethylsilyl aryltriflates. Typically, electron-deficient N-chloramines effectively react with aryne intermediates generated at elevated temperature with CsF, while less stable N-haloamines are found more efficient under milder, TBAF-mediated aryne formation at room temperature. Both protocols demonstrate a good level of regioselectivity and functional group tolerance. Efforts to elucidate the mechanism of NX insertion are also discussed. The practical value of this transformation is highlighted by rapid synthesis of novel analogues of the antipsychotic cariprazine.
Synthesis of α-Formylated <i>N</i>-Heterocycles and Their 1,1-Diacetates from Inactivated Cyclic Amines Involving an Oxidative Ring Contraction
作者:Fang Wang、Yan He、Miaomiao Tian、Xinying Zhang、Xuesen Fan
DOI:10.1021/acs.orglett.7b04029
日期:2018.2.2
cascade reactions of N-arylpiperidines or N-arylazepanes is presented. Mechanistically, the formation of the title compounds involves an unprecedented oxidative ring contraction of inactivated cyclic amines via Cu(OAc)2/KI/O2-promoted oxidativecleavage and reformation of the C–N bond. Interestingly, when PhI(OAc)2 was used in place of KI, 1,1-diacetates of the corresponding aldehydes were directly obtained
提出了一种由N-芳基哌啶或N-芳基氮杂环庚烷的级联反应合成吡咯烷-2-甲醛或四氢吡啶-2-甲醛的新方法。从机理上讲,标题化合物的形成涉及通过Cu(OAc)2 / KI / O 2促进的氧化裂解和C–N键的重整,使灭活的环状胺发生前所未有的氧化环收缩。有趣的是,当用PhI(OAc)2代替KI时,可以高效地直接获得相应醛的1,1-二乙酸酯。据我们所知,这是区域选择性C(sp 3)–H键功能化和C(sp 3)–使用铜盐和氧使饱和环胺的N键活化。
Reductive One Batch Synthesis of<i>N</i>-Arylpiperidines From Primary Amines and Glutaraldehyde
作者:Giancarlo Verardo、Angelo G. Giumanini、Grazia Favret、Paolo Strazzolini
DOI:10.1055/s-1991-26489
日期:——
The construction of the piperidine ring about an aromatic nitrogen atom, by a 5C + N reductive condensation reaction, using glutaraldehyde (pentanedial) and sodium borohydride in acidic water/methanol medium is described. The reaction is fast, affords good to excellent yields and appears insensitive to electronic effects and severe steric hindrance; it is found to be compatible with a large variety of aryl substituents, including nitro and oxo groups.
Synthesis of β-Dicarbonylated Tetrahydropiperidines via Direct Oxidative Cross-Coupling between Different C(sp<sup>3</sup>)–H Bonds
作者:Fang Wang、Xinying Zhang、Yan He、Xuesen Fan
DOI:10.1021/acs.joc.9b02924
日期:2020.2.21
followed by their radical addition and further oxidation of the addition adduct. To our knowledge, this is the first example in which β-dicarbonyl-substituted tetrahydropiperidines were prepared using readily available saturated cyclic amines as substrates and inexpensive and ubiquitous methyl ketones as dicarbonylation reagents. In addition, the product thus obtained could be easily transformed into