Synthesis of indenones
In the presence of a rhodium catalyst, paraformaldehyde enables a CO gas-free carbonylative cyclization of alkynes with 2-bromophenylboronic acids to yield indenone derivatives. Rhodium-catalyzed decarbonylation of formaldehyde is followed by carbonylation of alkynes with 2-haloboronic acids, respectively, leading to efficient whole carbonylation.
T. Morimoto, K. Yamasaki, A. Hirano, K. Tsutusmi, N. Kagawa, K. Kakiuchi, Y. Harada, Y. Fukukomoto, N. Chatani, T. Nishioka, Org. Lett., 2009, 11, 1777-1780.
A facile, efficient, and large-scale strategy for the synthesis of N-(1-Oxo-1H-inden-2-yl)benzamide derivatives via domino reaction between aryl aldehydes, hippuric acid, and acetic anhydride is catalyzed by HPW@nano-SiO2 under microwave irradiation. The reaction conditions are very simple and offer convenient isolation of the product. Moreover, the catalyst can be re-used up to five times after simple filtration.
M. Rostami, A. R. Khosropour, V. Mirkhani, I. Mohammadpoor-Baltork, M. Moghadam, S. Tangestaninejad, Synlett, 2011, 1677-1682.
One-pot tandem Meyer-Schuster rearrangement of arylpropynols and successive radical cyclization with disulfides enables the synthesis of 2-sulfenylindenone derivatives in good yields. The reaction tolerates a number of functional groups.
X.-S. Zhang, J.-Y. Jiao, X.-H. Zhang, B.-L. Hu, X.-G. Zhang, J. Org. Chem., 2016, 81, 5710-5716.