A metal-free dual C(sp3)–H bond functionalization of saturated cyclic ethers via photooxidative singlet oxygen-mediated ringopening and ring closing has been developed, providing a method for generating hydrobenzofurans/pyrans/dioxins. Mechanistic studies have confirmed that ring-opening intermediates were effectively generated by singlet oxygen-mediated C(sp3)–H activation and efficiently reacted
In Situ Generated Magnesium Cyanide as an Efficient Reagent for Nucleophilic Cyanation of Nitrosoalkenes and Parent Nitronates
作者:Pavel Yu. Ushakov、Andrey A. Tabolin、Sema L. Ioffe、Alexey Yu. Sukhorukov
DOI:10.1002/ejoc.201801761
日期:2019.3.7
In situ generated magnesium cyanide is a convenient, readily available, non‐volatile and organic‐soluble reagent for hydrocyanation reactions. Efficient nucleophilic cyanation of π‐electrophiles such as nitronates, conjugated nitrosoalkenes, imines, α,β‐unsaturated ketones, methylenemalonates and azoalkenes was demonstrated.
Facile synthesis of cyanofurans via Michael-addition/cyclization of ene–yne–ketones with trimethylsilyl cyanide
作者:Yue Yu、Yang Chen、Wanqing Wu、Huanfeng Jiang
DOI:10.1039/c6cc08320j
日期:——
We have developed a Michael-addition/cyclization procedure between ene-yne-ketones and TMSCN under metal-free conditions. A wide range of cyanofurans were delivered in high yields, which could be further transformed to a...
Oxidative Conversion of α,α-Disubstituted Acetamides to Corresponding One-Carbon-Shorter Ketones Using Hypervalent Iodine (λ<sup>5</sup>) Reagents in Combination with Tetraethylammonium Bromide
作者:Eknath V. Bellale、Dinesh S. Bhalerao、Krishnacharya G. Akamanchi
DOI:10.1021/jo801580g
日期:2008.12.5
Alpha,alpha-disubstituted acetamides undergo oxidative dehomologation to give one-carbon-shorter ketones when reacted with a hypervalent iodine (lambda(5)) reagent in combination with tetraethylammonium bromide (TEAB) in various solvents. In further studies, one such combination of a hypervalent iodine (lambda(5)) reagent, o-iodoxybenzoic acid, and TEAB has been established as a new, mild, efficient
Carbonucleophiles such as malonate esters, ß-keto esters, phenylacetate ester, and phenylacetonitrile were acetonylated in high yields by allylation with isopropyl (or methyl) 2-methylene-3,5-dioxahexyl carbonate (4b or 4a) in the presence of palladium-phosphine catalyst under neutral conditions, followed by acidic hydrolysis. Adopting this procedure dihydrojasmone (7) was prepared from ethyl 3-oxononanoate (6) in an overall yield of 72%.