42202-44-8Relevant articles and documents
Development of an Efficient Synthesis of rac-3-Demethoxyerythratidinone via a Titanium(III) Catalyzed Imine-Nitrile Coupling
Luu, Hieu-Trinh,Streuff, Jan
, p. 139 - 149 (2019/01/04)
We herein describe the evolution of a rapid, high-yielding synthesis of the erythrina alkaloid 3-demethoxyerythratidinone. The natural product is assembled in six steps from commercial precursors in 30–35 % overall yield and with only two chromatographical purification operations. The key step is a titanium(III) catalyzed umpolung reaction in form of a reductive imine–nitrile coupling that can be combined with a subsequent cyclization reaction on a 50 mmol scale. Furthermore, optimized Wacker oxidation conditions enable the selective alkene oxidation in the presence of a tertiary amine functionality, which has been a problem in previous syntheses of erythrina alkaloids. The racemic route can be used to prepare the natural product on gram scale and the results may be useful for the synthesis of related alkaloids.
A Titanium(III)-Catalyzed Reductive Umpolung Reaction for the Synthesis of 1,1-Disubstituted Tetrahydroisoquinolines
Luu, Hieu-Trinh,Wiesler, Stefan,Frey, Georg,Streuff, Jan
supporting information, p. 2478 - 2481 (2015/05/27)
A catalytic reductive C1-acylation of 3,4-dihydroisoquinolines is presented that gives direct access to 1,1-disubstituted tetrahydroisoquinolines. The reaction is a titanium(III)-catalyzed reductive umpolung process in which nitriles act as effective acylation agents. The method is highly chemo- and regioselective and is demonstrated in 20 examples. It is well-suited for the large-scale synthesis of functionalized tetrahydroisoquinoline products, which is exemplified in the form of a six-step synthesis of (±)-3-demethoxyerythratidinone. (Figure Presented).
New approach to the synthesis of phosphorodichloridites, phosphorochloridites, and trialkyl phosphites
Majewski, Piotr
experimental part, p. 942 - 955 (2010/01/17)
Different trivalent organophosphorus esters such as phosphorodichloridites, phosphorochloridites, and mixed trialkyl phosphites have been easily synthesized in good yields using a HCl-catalyzed reaction of the corresponding chlorophosphine and alkoxytrimethylsilane by mutual exchange of the alkoxy and chlorine ligand pIIICl/ROSiR′3; exchange reaction). Chemoselectivity of the exchange reaction with primary and secondary alkoxytrimethylsilanes, as well as with alkoxytrimethylsilanes and thioalkoxytrimethylsilanes, respectively, has also been examined. It has been also found that the substitution reaction of chlorophosphines with secondary amine occurs more rapidly than the exchange reaction with ROSiR′ 3.
