34119-82-9Relevant academic research and scientific papers
C(sp3)-H Bond Arylation and Amidation of Si-Bound Methyl Group via Directing Group Strategy
Han, Jie-Lian,Qin, Ying,Zhao, Dongbing
, p. 6020 - 6026 (2019/06/25)
Silylmethyl functionalization provides a general and efficient access to diverse organosilanes. The traditional methods for silylmethyl functionalization often involved silylmethylmetals or silylmethylhalides. In recent years, a C-H activation strategy has become one of the most attractive alternatives in organic synthesis. We envisioned that the attachment of a coordinating group at silicon of methylsilanes provides the opportunity to modify the silylmethyl group via directed C-H bond functionalization. However, despite employment of silicon tethers bearing a directing group (DG) for C(sp2)-H functionalization has been well established due to the fact that the silicon tethers are easily installable and removable/modifiable, applying this concept toward C(sp3)-H functionalization remains underdeveloped. Herein, we successfully develop IrIII/RhIII-catalyzed C-H bond arylation/amidation of silyl methyl group by using directing group strategy, which constitutes the most powerful access to benzylsilanes and amino-substituted silanes. Moreover, we demonstrated that the pyridine directing group on silicon atom can be easily removed, and the starting materials can also be efficiently recovered, which are different from those of pyridine-directed C-H functionalization of C-bound methyl group.
Chiral-Organotin-Catalyzed Kinetic Resolution of Vicinal Amino Alcohols
Yang, Hui,Zheng, Wen-Hua
supporting information, p. 16177 - 16180 (2019/11/03)
A highly efficient kinetic resolution of racemic amino alcohols has been achieved for the first time with a chiral tin catalyst. A chiral organotin compound with 3,4,5-trifluorophenyl groups at the 3,3′-positions of the binaphthyl framework enabled this transformation with excellent yield and high enantioselectivity. The process tolerates aryl- and alkyl-substituted amino alcohols and a variety of other substrates, affording the corresponding products in high enantioselectivity and with s factors up to >500.
Enantioselective Aminohydroxylation of Styrenyl Olefins Catalyzed by an Engineered Hemoprotein
Cho, Inha,Prier, Christopher K.,Jia, Zhi-Jun,Zhang, Ruijie K.,G?rbe, Tamás,Arnold, Frances H.
supporting information, p. 3138 - 3142 (2019/02/01)
Chiral 1,2-amino alcohols are widely represented in biologically active compounds from neurotransmitters to antivirals. While many synthetic methods have been developed for accessing amino alcohols, the direct aminohydroxylation of alkenes to unprotected, enantioenriched amino alcohols remains a challenge. Using directed evolution, we have engineered a hemoprotein biocatalyst based on a thermostable cytochrome c that directly transforms alkenes to amino alcohols with high enantioselectivity (up to 2500 TTN and 90 % ee) under anaerobic conditions with O-pivaloylhydroxylamine as an aminating reagent. The reaction is proposed to proceed via a reactive iron-nitrogen species generated in the enzyme active site, enabling tuning of the catalyst's activity and selectivity by protein engineering.
An Efficient Catalytic Amidation of Esters Promoted by N-Heterocyclic Carbenes
Chen, Ling-Yan,Wu, Mei-Fang
, p. 1595 - 1602 (2019/03/26)
An efficient NHC-catalyzed amidation between esters and amines or hydrazines is described. This strategy was tolerant for a wide scope of substrates, affording a series of amides (or hydrazides) in good to excellent yields (60-96%) under simple conditions. The approach was also used to synthesize the pharmaceutically relevant antidepressant moclobemide in 85% yield.
Direct Amidation of Carboxylic Acids through an Active α-Acyl Enol Ester Intermediate
Xu, Xianjun,Feng, Huangdi,Huang, Liliang,Liu, Xiaohui
, p. 7962 - 7969 (2018/06/18)
The development of a highly efficient and simple protocol for the direct amidation of carboxylic acids is described employing ynoates as novel coupling reagents. The transformation proceeds in good to excellent yields via in situ α-acyl enol ester intermediates formation under mild reaction conditions. This useful method has been demonstrated for a range of substrates to provide a succinct access to structurally diverse amides, including key intermediates of glibenclamide, tiapride hydrochloride, and nateglinide, and can be conducted on a mole scale.
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.
Remote C(sp3)-H Oxygenation of Protonated Aliphatic Amines with Potassium Persulfate
Lee, Melissa,Sanford, Melanie S.
supporting information, p. 572 - 575 (2017/02/10)
This letter describes the development of a method for selective remote C(sp3)-H oxygenation of protonated aliphatic amines using aqueous potassium persulfate. Protonation serves to deactivate the proximal C(sp3)-H bonds of the amine substrates and also renders the amines soluble in the aqueous medium. These reactions proceed under relatively mild conditions (within 2 h at 80 °C with amine as limiting reagent) and do not require a transition metal catalyst. This method is applicable to a variety of types of C(sp3)-H bonds, including 3°, 2°, and benzylic C-H sites in primary, secondary, and tertiary amine substrates.
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.
Site-Selective Silylation of Aliphatic C-H Bonds Mediated by [1,5]-Hydrogen Transfer: Synthesis of α-Sila Benzamides
Liu, Pei,Tang, Jinghua,Zeng, Xiaoming
, p. 5536 - 5539 (2016/11/17)
The first example of site-selective silylation of C(sp3)-H bonds mediated by a [1,5]-hydrogen transfer is reported. This reaction occurs selectively at the α-position of benzamides with a combination of tert-butylmagnesium chloride and a catalytic amount of 4,4′-di-tert-butylbipyridine (dtbpy) ligand and provides a facile route for the creation of biologically interesting α-sila benzamides. Late-stage functionalization of the incorporated silyl moieties facilitates the synthesis of N-formyl, cis-enamine, β-hydroxyl, amino, and pyrrole-containing derivatives.
Green synthesis of benzamides in solvent- and activation-free conditions
Alalla, Affef,Merabet-Khelassi, Mounia,Aribi-Zouioueche, Louisa,Riant, Olivier
supporting information, p. 2364 - 2376 (2014/07/22)
Herein, we describe a clean and ecocompatible pathway for both N-benzoylation and N-acetylation of anilines, amines, diamines, and aminoalcohols using three enol esters with good yields. We have improved the use of vinyl benzoate for the direct introduction of a benzamido-moiety under solvent- and activation-free conditions. The recovered amides are easily isolated by crystallization. Copyright
