1627153-13-2Relevant articles and documents
Diastereotopic group selection in hydroxy-directed intramolecular C-H alkenylation of indole under oxidative palladium(II) catalysis
Kandukuri, Sandeep R.,Jiao, Lin-Yu,MacHotta, Axel B.,Oestreich, Martin
supporting information, p. 1597 - 1609 (2014/06/09)
Group-selective palladium(II)-catalyzed ring closures involving C-H bond alkenylation are reported. The cyclization precursors contain a prochiral bis(homoallylic) alcohol unit tethered to either an arene or an indole. The homobenzylic hydroxy group in these substrates is positioned to act as a directing group in the ortho-selective C-H bond activation prior to the cyclization event. Arene-derived precursors reacted poorly, even when applying a protocol that had proven effective in intermolecular hydroxy-directed C-H bond alkenylations. No asymmetric induction was obtained with chiral ligands, mono-N-protected amino acids (MPAAs) in particular. Conversely, the cyclization of indole-derived precursors was substantially more efficient, and installation of a substituent in the benzylic position rendered these intramolecular C-H bond alkenylations diastereoselective. The diastereotopic group selection is high with diastereomeric ratios ranging from dr=91:9 to 94:6.
