Ru‑Catalyzed Chelation-Assisted Alkenylation of Heteroatom Substituted Aromatics and Heteroaromatics with Alkenes and Alkynes
2Department of Chemistry, IISER-Pune, Pune
Transition-metal-catalyzed chelation-assisted ortho C‑H bond activation of hetero-atom substituted aromatic followed by alkenylation with alkenes or alkynes is one of the powerful methods for synthesizing di- and trisubstituted alkene derivatives in a highly regio- and stereoselective manner.1 It is important to mention that the alkene derivatives found widespread application in organic materials, natural products and drug molecules. The selection of directing group is highly important in order to success this type of alkenylation reaction. While the C‑H bond activation reaction in the presence of strong directing groups is well documented in the literature. But, activation in the presence of weak directing groups such as aldehydes, esters, cyano, sulfoxide and ketones are still a challenging task.
In this presentation, we would like to discuss a ruthenium‑catalyzed ortho-alkenylation of hetero-atom substituted aromatics such as aromatics and heteroaromatic carbonyl compounds with alkenes. In the reaction, we have prepared disubstituted alkene derivatives in a highly regio- and stereoselective manner.2a-c It is interesting to note that this catalytic reaction was conducted under the air atmosphere and only catalytic amount of terminal oxidant Cu(OAc)2 has been used, the remaining amount of copper source being reoxidized by air. In addition, we would like to discuss a weakly coordinating S=O assisted hydroarylation of aromatic sulfoxides with alkynes in the presence of ruthenium catalyst leading to trisubstituted alkenes in good to excellent yields in a highly regio- and stereoselective manner.2d
References
1. (a) Arokiam, P. B.; Bruneau, C.; Dixneuf, P. H. Chem. Rev., 2012, 112, 5879. (b) Ackermann, L. Acc. Chem. Res., 2014, 47, 281.
2. (a) Kishor, P.; Jeganmohan, M. Org. Lett. 2011, 13, 6144. (b) Kishor, P.; Jeganmohan, M. Org. Lett. 2012, 14, 1134. (c) Kishor, P.; Pimparkar, S.; Padmaja, M.; Jeganmohan, M. Chem. Commun. 2012, 48, 7140. (d) Kishor, P.; Jeganmohan, M. Chem. Commun. 2014, in press. (e) Kishor, P.; Jeganmohan, M. Chem. Commun. 2013, 49, 9651. (g) Kishor, P.; Jeganmohan,Chem. Eur. J. 2014, 20, 4092.
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