Iron(II) catalyzed reductive radical cyclization reactions of bromoacetals in the presence of NaBH4: optimization studies and mechanistic insights
作者:Sara H. Kyne、Christophe Lévêque、Shiwen Zheng、Louis Fensterbank、Anny Jutand、Cyril Ollivier
DOI:10.1016/j.tet.2016.08.039
日期:2016.12
5-Exo-trig radical reductivecyclization reactions of bromoacetals are catalyzed by iron in the presence of the reducing agent NaBH4. Both iron(II) and iron(III) were found to effectively mediate these reactions. As shown by cyclic voltammetry, iron(III) can be reduced to an iron(II) precatalyst before passing through an identical reaction mechanism in which monoelectronic activation of the substrate
Single-Electron-Transfer Strategy for Reductive Radical Cyclization: Fe(CO)<sub>5</sub> and Phenanthroline System
作者:Joon Young Hwang、Jong Hwa Baek、Tae Il Shin、Jung Ha Shin、Jae Won Oh、Kwang Pyo Kim、Youngmin You、Eun Joo Kang
DOI:10.1021/acs.orglett.6b02375
日期:2016.10.7
electron-transfer strategy using low-valent iron pentacarbonyl [Fe(CO)5] to generate radical species from alkyl iodides was achieved. A range of pyrrolidines, tetrahydrofurans, and carbocycles were synthesized via 5-exo cyclization reactions of alkyl radical intermediates generated by electron transfer from a system involving Fe(CO)5, 1,10-phenanthroline, and diisopropylamine. Moreover, tandem addition
A Free‐Radical Reduction and Cyclization of Alkyl Halides Mediated by FeCl
<sub>2</sub>
作者:Feba Thomas Pulikottil、Ramadevi Pilli、Vetrivelan Murugesan、Chandu G. Krishnan、Ramesh Rasappan
DOI:10.1002/cctc.201900230
日期:2019.5.20
Iron mediated catalytic reactions are of great interest in the field of organic synthesis because they are economic and naturally abundant. However, the use of iron catalyst in the field of free radicalcyclization or reduction of alkyl halides remains limited. Here we describe the use of an unprecedented combination of iron and zinc in the reduction and 5‐exo‐trig radicalcyclization of alkyl halides
Indium hydride: a novel radical initiator in the reduction of organic halides with tributyltin hydride
作者:Katsuyuki Inoue、Akemi Sawada、Ikuya Shibata、Akio Baba
DOI:10.1016/s0040-4039(01)00816-4
日期:2001.7
Dichloroindium hydride (Cl2InH), which was generated in situ by transmetallation between tributyltinhydride and indium trichloride, acted as a novel radical initiator for the reduction of organic halides with tributyltinhydride. The reaction was revealed to proceed through a radical process under non-oxygen conditions at room temperature, and to be applicable to intramolecular radical cyclizations
Copper-Catalyzed Dicarbofunctionalization of Unactivated Olefins by Tandem Cyclization/Cross-Coupling
作者:Surendra Thapa、Prakash Basnet、Ramesh Giri
DOI:10.1021/jacs.7b01922
日期:2017.4.26
We present a strategy that difunctionalizes unactivated olefins in 1,2-positions with two carbon-based entities. This method utilizes alkyl/arylzinc reagents derived from olefin-tethered alkyl/aryl halides that undergo radical cyclization to generate C(sp3)-Cu complexes in situ, which are intercepted with aryl and heteroaryl iodides. A variety of (arylmethyl)carbo- and heterocycles (N, O) can be synthesized