1174194-07-0Relevant articles and documents
Chemoselective Biohydrogenation of Alkenes in the Presence of Alkynes for the Homologation of 2-Alkynals/3-Alkyn-2-ones into 4-Alkynals/Alkynols
Colombo, Danilo,Brenna, Elisabetta,Gatti, Francesco G.,Ghezzi, Maria Chiara,Monti, Daniela,Parmeggiani, Fabio,Tentori, Francesca
, p. 2638 - 2648 (2019/05/16)
The chemoselective hydrogenation of alkenes in the presence of alkynes is a very challenging transformation to achieve with traditional chemical methods. The development of an effective procedure to perform this transformation would enrich the tool-kit available to organic chemists for the development of useful synthetic routes, and the creation of novel structural motifs. The reduction of activated alkene bonds by ene-reductases (ERs) is completely chemoselective, because of the mechanism of the reaction. Thus, we investigated the use of ERs belonging to the Old Yellow Enzyme family for the reduction of α,β-unsaturated aldehydes with a conjugated C≡C triple bond at the γ position. This reaction was exploited as the key step for the development of an effective homologation route to convert aryl and alkyl substituted propynals and butynones into 4-alkynals and 4-alkynols, avoiding some troublesome or hazardous steps of known synthetic routes. (Figure presented.).
Asymmetric organocatalytic formal alkynylation and alkenylation of α,β-unsaturated aldehydes
Nielsen, Martin,Jacobsen, Christian Borch,Paixao, Marcio W.,Holub, Nicole,Jorgensen, Karl Anker
supporting information; experimental part, p. 10581 - 10586 (2009/12/25)
A highly stereoselective organocatalytic one-pot protocol for the formal alkynylation and alkenylation of α,β-unsaturated aldehydes using novel chemistry based on β-keto heterocyclic sulfones is presented. The organocatalytic step is catalyzed by a prolinol derivative and allows for the formation of important optically active compounds. Further transformations of the β-keto heterocyclic sulfone moiety, based on new developments of the Smiles rearrangement through a process parallel to the Julia-Kocienski reaction, were performed leading to β-alkynylated aldehydes and 3-alkenylated alcohols. The scopes of both transformations are demonstrated by the synthesis of various optically active alkynes and alkenes. Furthermore, different transformations of the aldehyde and the alcohol functionality were performed. Finally, the proposed mechanisms for both the alkynylation and alkenylation of α,β-unsaturated aldehydes are outlined.
