@article{95f9b944fa174387872764184acdc816,
title = "Zn(OTf)2-mediated annulations of: N -propargylated tetrahydrocarbolines: Divergent synthesis of four distinct alkaloidal scaffolds",
abstract = "Intramolecular hydroarylations of N-propargylated tetrahydrocarbolines were efficiently mediated using a unique combination of Zn(OTf)2 with t-BuOH under neutral conditions. Use of the artificial force induced reaction method in the global reaction route mapping strategy provided insights into the Zn(OTf)2-mediated hydroarylations and the associated intriguing solvent effects of t-BuOH facilitating a protodezincation process without a Br{\o}nsted acid activator. We systematically implemented three distinct hydroarylations as well as an unanticipated α-alkenylation of a carbonyl group to obtain the four alkaloidal scaffolds 2-4, and 18. Zn(OTf)2-mediated annulation of 1c proceeded through kinetic formation of the spiroindole 3c followed by an alkenyl shift and concomitant retro-Mannich-type fragmentation to furnish azepino[4,5-b]indole 2 framework. Substituents on substrate 1 in the vicinity of the reaction sites substantially affected the mode of the divergent annulations. Judicious choices of the substituents, solvent and reaction conditions enabled programmable divergent synthesis of the four distinct skeletons.",
author = "Sadaiwa Yorimoto and Akira Tsubouchi and Haruki Mizoguchi and Hideaki Oikawa and Yoshiaki Tsunekawa and Tomoya Ichino and Satoshi Maeda and Hiroki Oguri",
note = "Funding Information: We are grateful for nancial supports from the Japan Science and Technology Agency (JST) (JPMJPR13K3) “Precursory Research for Embryonic Science and Technology” (PRESTO to H. O.) and “Core Research for Evolutional Science and Technology (CREST to S. M.)” for projects of “Molecular technology and creation of new functions”, JSPS KAKENHI (Grant No. 15H03117 to H. O., Grant No. JPMJCR14L5 to S. M.), the Asahi Grass Foundation (H. O.), and Astellas Foundation for Research on Metabolic Disorders (H. O.). This work was also inspired by the international and interdisciplinary environments of the JSPS Asian CORE Program, “Asian Chemical Biology Initiative” as well as the JSPS A3 Foresight Program “Asian Chemical Probe Research Hub”. Institute for Chemical Reaction Design and Discovery (ICReDD) was established by World Premier International Research Initiative (WPI), MEXT, Japan. Publisher Copyright: {\textcopyright} 2019 The Royal Society of Chemistry.",
year = "2019",
doi = "10.1039/c9sc01507h",
language = "English",
volume = "10",
pages = "5686--5698",
journal = "Chemical Science",
issn = "2041-6520",
publisher = "Royal Society of Chemistry",
number = "22",
}