Total synthesis of (±)-tangutorine and chiral HPLC separation of enantiomers

Cyclization of Cyanoethylated Ketones as a Route to 6‐Substituted Indole Derivatives

“…Yield 65%, mp 133–134°C (lit. mp 133–134°C). The NMR data were in agreement with data reported in the literature .…”

Biomimetic Synthesis of Ornithine/Arginine and Lysine‐Derived Alkaloids: Selected Examples

“…Indeed, reduction of 163 with sodium borohydride gave tangutorine (164) after recrystallization to isolate the major diastereomer of the (75 : 25) mixture [85]. This straightforward strategy also cast doubt on the previously proposed biosynthetic pathway to tangutorine (164), involving a complex rearrangement of a yohimbine-type indolomonoterpenic precursor, proposed by Jokela and colleagues (Scheme 1.43) [86]. Interestingly, compound 166, resulting from a direct Pictet-Spengler reaction of the aldehyde function of 52 with tryptamine, was also isolated from the reaction.…”

“…In 2010, one of us published a comprehensive review covering the state of knowledge and detailing the isolation, structure determination (and revision), and the biomimetic syntheses of Nitraria alkaloids [87]; the interested reader is directed to this article as well as to older reviews [86]. Many achievements in biomimetic synthesis of Nitraria alkaloids have been disclosed by the Koomen group [88] and the Husson group [89].…”

A Formal [3 + 3] Cycloaddition Approach to Natural‐Product Synthesis

“…[120] This strategy was also evident in Jokela's sole total synthesis of tangutorine (253). [121] We envisioned that tangutorine should be attainable from pentacycle 256, and to construct pentacycle 256 we could use an intramolecular aza- [3 ϩ 3] cycloaddition with α,β-unsaturated iminium salt 257. The α,β-unsaturated aldehyde precursor to 257a could be obtained from condensation of amino alcohol 258 with 1,3-cyclohexanedione.…”