14468-80-5Relevant articles and documents
Construction of a (3 aR,4 R,9 bR)-Hexahydropyrroloquinoline by Stereoselective Hydrogen-Mediated Domino Cyclization
Yamada, Masatoshi,Usutani, Hirotsugu,Ito, Tatsuya,Yamano, Mitsuhisa
, p. 535 - 547 (2019)
A novel practical asymmetric route to a chiral hexahydropyrroloquinoline derivative 2, a key fragment of TAK-480, is reported. The corresponding substrate, enamine 19, was directly transformed to a diastereopure and enantiopure (3aR,4R,9bR)-hexahydropyrroloquinoline 16 through a rhodium-catalyzed hydrogen-mediated domino cyclization consisting of four steps; (1) asymmetric hydrogenation of enamine, (2) hydrogenation of iminium olefin in a lactam, (3) dehydration and catalytic sulfonation, and (4) cis-selective intramolecular cyclization. A tuned asymmetric catalyst [Rh(cod){(2S,4S)-PTBP-SKEWPHOS}]OTf that we previously developed was found to promote improved reaction activity and be the most suitable catalyst for a multikilogram manufacturing for preclinical research. The resulting stereoselective domino cyclization drastically reduced several synthetic steps, and the resulting waste compared to the discovery route that required chiral preparative high-performance liquid chromatography and silica gel column separation.
One-Pot Double-Annulation Strategy for the Synthesis of Unusual Fused Bis-Heterocycles
Abdul-Rashed, Shukree,Alachouzos, Georgios,Brennessel, William W.,Frontier, Alison J.
supporting information, p. 4350 - 4354 (2020/06/04)
A novel metal-free double-annulation cascade for the construction of unusual fused heterocyclic systems is described. This simple protocol enables the sequential assembly of two rings in one pot from two simple precursors. Acidic conditions promote the condensation and the intramolecular alkynyl Prins reaction of an enyne or arenyne alcohol with a cyclic hemiaminal to form a five-, six-, or seven-membered oxacycle followed by a seven-or eight-membered azacycle. In this transformation, chemical complexity is rapidly generated with the formation of three new bonds (one C-O, one C-C, and one C-N) in one synthetic operation. The strategy is modular and relatively general, providing access to a series of unique fused bicyclic scaffolds.
RHODIUM CATALYST AND METHOD FOR PRODUCING AMINE COMPOUND
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Paragraph 0304, (2015/02/25)
[Problem] Provision of a superior rhodium catalyst and a production method of amine compound. [Solving Means] A rhodium complex coordinated with a compound represented by the formula
