The first asymmetric propargylic radical cyanation was realized through a dual photoredox and copper catalysis. An organic photocatalyst serves to both generate propargyl radicals and oxidize Cu(I) species to Cu(II) species. A chiral Cu complex functions as an efficient organometallic catalyst to resemble the propargyl radical and cyanide in an enantio-controlled manner. Thus, a diverse range of optically active propargyl cyanides were produced with high reaction efficiency and enantioselectivities (28 examples, 57−97% yields and 83−98% ee). Moreover, mechanistic investigations including experiments and density functional theory calculations were performed to illustrate on the reaction pathway and stereochemical results.
1,3-Dienes are readily available feedstocks that are widely used in the laboratory and industry. However, the potential of converting 1,3-dienes into value-added products, especially chiral products, has not yet been fully exploited. By synergetic photoredox/copper catalysis, we achieve the first visible-light-induced, enantioselective carbocyanation of 1,3-dienes by using carboxylic acid derivatives and trimethylsilyl cyanide. Under mild and neutral conditions, a diverse range of chiral allyl cyanides are produced in generally good efficiency and with high enantioselectivity from bench-stable and user-safe chemicals. Moreover, preliminary results also confirm that this success can be expanded to 1,3-enynes and the four-component carbonylative carbocyanation of 1,3-dienes and 1,3-enynes.
Chiral catalysts tolerating photochemical reactions are in great demand for the vast development of visible-lightinduced asymmetric synthesis.N ow,c hiral octahedral complexes based on earth-abundant metal and chiral N 4 ligands are reported. One well-defined chiral Co II -complex is shown to be an efficient catalyst in the visible-light-induced conjugated addition of enones by alkyl and acyl radicals,p roviding synthetically valued chiral ketones and 1,4-dicarbonyls in 47-> 99 %yields with up to 97:3 e.r.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.
The advances on transition-metal catalysed asymmetric couplings with light intervention in recent years was summarized in this review. In order to better meet the needs of modern chemistry, further research outlook was also proposed.
An unprecedented triple catalytic, general ring-opening cyanation reaction of cyclopropyl ketones to construct γ-cyanoketones is described. The key is to merge photoredox catalysis with Lewis acid catalysis and copper catalysis...
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