4561-43-7Relevant academic research and scientific papers
Catalyst-Free Electrophilic Ring Expansion of N-Unprotected Aziridines with α-Oxoketenes to Efficient Access 2-Alkylidene-1,3-Oxazolidines
Chen, Xingpeng,Huang, Zhengshuo,Xu, Jiaxi
, p. 3098 - 3108 (2021/05/10)
2-(2-Oxoalkylidene)-1,3-oxazolidine derivatives were synthesized in good to excellent yields regiospecifically through the catalyst-free electrophilic ring expansion of N-unprotected aziridines and the ketene C=O double bond of α-oxoketenes, in situ generated from the microwave-assisted Wolff rearrangement of 2-diazo-1,3-diketones. The ring expansion predominantly underwent an SN1 process and the hydrogen bond decides the (E)-configuration of products. (Figure presented.).
Lewis Acid-Catalyzed Addition of Benzophenone Imine to Epoxides Enables the Selective Synthesis and Derivatization of Primary 1,2-Amino Alcohols
Leitch, David C.,Lim, John Jin
, p. 641 - 649 (2018/05/14)
Benzophenone imine was found to be an effective ammonia surrogate for the selective preparation of primary 1,2-amino alcohols from epoxides, including enantiopure epichlorohydrin, in the presence of catalytic Y(OTf)3. High-throughput screening of 48 Lewis acids quickly identified Y(OTf)3 as an effective mediator of the addition reaction under mild conditions. Following acidic hydrolysis, the primary amino alcohol salt is revealed and partitions into the aqueous solution, while the benzophenone byproduct is easily removed by simple extraction with ethyl acetate. These ammonium salts can be directly Boc-protected or further derivatized without isolation to form benzamides and sulfonamides under Schotten-Baumann-type conditions in up to 79% isolated yield over three steps. This methodology has been used to prepare key intermediates for the synthesis of PRMT5 inhibitors with high enantiopurity as well as numerous other amide and sulfonamide derivatives.
Diamine-Tethered Bis(thiourea) Organocatalyst for Asymmetric Henry Reaction
Otevrel, Jan,Bobal, Pavel
, p. 8342 - 8358 (2017/08/23)
We have developed a novel multifunctional C2-symmetric biphenyl-based diamine-tethered bis(thiourea) organocatalyst, which was tested in the asymmetric Henry reaction. Under thoroughly optimized conditions, the catalyst provided exceptionally high yields and excellent enantioselectivities especially for electron-deficient aromatic and heterocyclic substrates. Due to a high affinity of the catalyst to silica gel, a simple chromatography-free nitroaldol isolation procedure was feasible. Preliminary kinetic and spectroscopic experiments were performed in order to complete the mechanistic picture of the organocatalyzed nitroaldolization process. Finally, the developed synthetic strategy was successfully applied to the catalytic enantioselective syntheses of enantiopure (S)-econazole and (R)-mirabegron a late-stage intermediate.
Aminohydroxylation of olefins with iminopyridinium ylides by dual Ir photocatalysis and Sc(OTf)3catalysis
Miyazawa, Kazuki,Koike, Takashi,Akita, Munetaka
, p. 7813 - 7820 (2016/11/16)
We have developed a new strategy for catalytic aminohydroxylation of olefins with an N-protected iminopyridinium ylide as the amine source. Iminopyridinium ylides N-protected with TFAc (trifluoroacetyl), Boc (tert-butoxycarbonyl), Troc (2,2,2-trichloroethoxycarbonyl), and Alloc (allyloxycarbonyl) groups serve as N-centered radical precursors when combined with fac-[Ir(ppy)3] photocatalysis and Sc(OTf)3catalysis. The dual Ir photoredox/Sc(OTf)3catalysis proves to be effective for aminohydroxylation of olefins under mild reaction conditions to provide 2-aminoalcohol derivatives bearing a primary amino group.
SYNTHESIS OF α-AMINO KETONE HYDROCHLORIDES VIA CHEMOSELECTIVE HYDROGENATION OF α-NITRO KETONES
Tamura, Rui,Oda, Daihei,Kurokawa, Hiroshi
, p. 5759 - 5762 (2007/10/02)
Chemoselective hydrogenation of various α-nitro ketones was accomplished with 5percent Pt sulfide on carbon as a catalyst to afford α-amino ketone hydrochlorides in good yields.
