Copper-mediated oxidative [3 + 2]-annulation of nitroalkenes and pyridinium imines: efficient synthesis of 3-fluoro- and 3-nitro-pyrazolo[1,5-<i>a</i>]pyridines
作者:Vladimir A. Motornov、Andrey A. Tabolin、Yulia V. Nelyubina、Valentine G. Nenajdenko、Sema L. Ioffe
DOI:10.1039/c9ob02668a
日期:——
efficient route to pyrazolo[1,5-a]pyridines by Cu(OAc)2-promoted oxidative [3 + 2]-annulation of nitroalkenes with in situ generated pyridinium imines is developed. The reaction with α-fluoronitroalkenes enables the first preparative synthesis of 3-fluoro-pyrazolo[1,5-a]pyridines. Cycloaddition with α-unsubstituted nitroalkenes provides access to 3-nitro-pyrazolo[1,5-a]pyridines in excellent yields. A broad
When activated with Takemoto’scatalyst, 1,2‐keto esters constitute versatile nucleophiles in the Michaeladdition reaction with nitroalkenes affording synthetically valuable, optically active anti‐adducts in very good yields and high enantiomeric excesses.
An Easy Synthesis of Monofluorinated Derivatives of Pyrroles from β-Fluoro-β-Nitrostyrenes
作者:Alexander S. Aldoshin、Andrey A. Tabolin、Sema L. Ioffe、Valentine G. Nenajdenko
DOI:10.3390/molecules26123515
日期:——
conjugate addition of pyrroles to β-Fluoro-β-nitrostyrenes was investigated. The reaction was found to proceed under solvent-free conditions to form 2-(2-Fluoro-2-nitro-1-arylethyl)-1H-pyrroles. The effectiveness of this approach was demonstrated through the preparation of a series of the target products in a quantitative yield. The kinetics of a conjugate addition of pyrrole was studied in detail
作者:Alexander S. Aldoshin、Andrey A. Tabolin、Sema L. Ioffe、Valentine G. Nenajdenko
DOI:10.1002/ejoc.201900573
日期:2019.7.23
A new procedure for preparation of a previously unknown class of monofluorinated 3‐vinyl indoles is reported. This strategy is based on a one‐pot two‐step process involving a preliminary uncatalyzed Michael addition of β‐fluoro‐β‐nitrostyrenes to indoles followed by a base‐induced elimination of nitrous acid. The unique role of fluorine for realization of this process was demonstrated.
Diels-Alder Reaction of β-Fluoro-β-nitrostyrenes. Synthesis of Mono-fluorinated Six-Membered Derivatives
作者:Roman V. Larkovich、Savva A. Ponomarev、Alexander S. Aldoshin、Andrey A. Tabolin、Sema L. Ioffe、Valentine G. Nenajdenko
DOI:10.1002/ejoc.202000054
日期:2020.5.10
TOC Text: The Diels‐Alder reaction of β‐fluoro‐β nitrostyrenes with some linear dienes is reported. The kinetic studies were carried out to reveal substituent effect and activation parameters of the reaction. A new family of monofluorinated cyclohexenes 2 was prepared. The further transformation of 2 into biphenyls 3 based on base‐induced elimination of HNO2 followed by oxidative aromatization were