Morimoto Tsumoru, Yamasaki Kae, Hirano Akihisa, Tsutsumi Ken, Kagawa Natsuko, Kakiuchi Kiyomi, Harada Yasuyuki, Fukumoto Yoshiya, Chatani Naoto, Nishioka Takanori
Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), Takayama, Ikoma, Nara 630-0192, Japan.
Org Lett. 2009 Apr 16;11(8):1777-80. doi: 10.1021/ol900327x.
The rhodium(I)-catalyzed reaction of alkynes with 2-bromophenylboronic acids in the presence of paraformaldehyde resulted in a CO gas-free carbonylative cyclization, yielding indenone derivatives. RhCl(BINAP) and RhCl(cod) were responsible for the decarbonylation of formaldehyde and the subsequent carbonylation of alkynes with 2-haloboronic acids, respectively, leading to efficient whole carbonylation. Sterically bulky and electron-withdrawing groups on unsymmetrically substituted alkynes favored the alpha-position of indenones.
