XI PhD-Chem Day
Bari, March 28, 2014
Palladium/norbornene-catalyzed synthesis of fluorenyl alcohols via
C–H activation
Marco Fontana, Marta Catellani, Elena Motti, Nicola Della Ca’
Department of Chemistry and Interuniversity Consortium Chemical Reactivity and Catalysis – CIRCC,
University of Parma, Parco Area Scienze, 17/A, I-43124 Parma, Italy
Abstract
In the frame of our research activity aimed at selective aromatic functionalization via C–H
activation we have previously described a palladium/norbornene-catalyzed reaction of an aryl
iodide and an ortho-bromobenzyl alcohol that affords either ortho-biarylcarbaldehyde/ketone or
dibenzopyran. The chemoselectivity primarily depends on the alcohol moiety of the latter substrate:
primary and tertiary alcohols exclusively or predominantly lead to aldehydes and dibenzopyrans,
respectively (eq. 1), while secondary alcohols give rise to a mixture of ketones and dibenzopyrans
with a varying ratio [1].
We have now found that the reaction of aryl iodides and secondary ortho-bromobenzyl alcohols in
the presence of palladium/norbornene as catalyst, Cs2CO3 as a base in toluene at 105 °C selectively
leads to the formation of fluorenyl alcohols [2] according to eq. 2.
The main features of the reaction will be discussed.
References
[1] E. Motti, N. Della Ca’, D. Xu, A. Piersimoni,E. Bedogni, Z.-M. Zhou, M. Catellani, Org. Lett. 2012, 14, 5792.
[2] Y.-B. Zhao, B. Mariampillai, D. A. Candito, B. Laleu, M. Li, M. Lautens, Angew. Chem. Int. Ed. 2009, 48, 1849.
*Corresponding author: Marco Fontana Tel: +39 0521 905415; fax: +39 0521 905472; e-mail address:
[email protected]