42307-60-8Relevant academic research and scientific papers
1,1-Diborylalkyl-1-Metal Compounds, Preparation Method Thereof, and Their Applications Toward Synthesis of 1,1-Diboronate Ester Compounds
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Paragraph 0238; 0242-0243, (2019/09/06)
The present invention relates to a 1,1-diborylalkyl-1-metal compound including one metal group together with two identical boron groups at the sp3 carbon center, and its use. Specifically, the present invention relates to development of novel organic reactions, synthesis of functional molecules, and synthesis of new drugs by applying the novel 1,1-diboryl-1-metal substituted alkyl compounds to various molecular libraries which could not be synthesized by conventional methodologies.
Generation and Application of (Diborylmethyl)zinc(II) Species: Access to Enantioenriched gem-Diborylalkanes by an Asymmetric Allylic Substitution
Lee, Yeosan,Park, Jinyoung,Cho, Seung Hwan
, p. 12930 - 12934 (2018/09/25)
We report the successful generation of (diborylmethyl)zinc(II) species by transmetallation beteween isolable (diborylmethyl)lithium and zinc(II) halide (X=Br, Cl) and their application in the synthesis of enantioenriched gem-diborylalkanes bearing a stereogenic center at the β-position of the diboryl groups by an asymmetric allylic substitution reaction. The reaction has a broad substrate scope, and various enantioenriched gem-diborylalkanes can be obtained in good yields with excellent enantioselectivity. Further elaboration of the enantioenriched gem-diborylalkanes provides access to a diverse set of valuable chiral building blocks.
Enantioselective Copper-Catalyzed Defluoroalkylation Using Arylboronate-Activated Alkyl Grignard Reagents
Wang, Minyan,Pu, Xinghui,Zhao, Yunfei,Wang, Panpan,Li, Zexian,Zhu, Chendan,Shi, Zhuangzhi
supporting information, p. 9061 - 9065 (2018/08/03)
A copper-catalyzed system has been introduced for the enantioselective defluoroalkylation of linear 1-(trifluoromethyl)alkenes through C-F activation to synthesize various gem-difluoroalkenes as carbonyl mimics. For the first time, arylboronate-activated alkyl Grignard reagents were uncovered in this cross-coupling reaction. Mechanistic studies confirmed that the tetraorganoborate complexes generated in situ were the key reactive species for this transformation.
Asymmetric rearrangement of racemic epoxides catalyzed by chiral Br?nsted acids
Zhuang, Minyang,Du, Haifeng
supporting information, p. 1460 - 1462 (2013/05/08)
This paper describes a chiral Br?nsted acid catalyzed asymmetric 1,2-rearrangement of racemic epoxides via a hydrogen-shift process for the synthesis of chiral aldehydes, and, followed by a reduction, a variety of optically active alcohols can be furnished in moderate yields with up to 50% ee. Especially, a facile one-pot synthesis of chiral alcohols directly from simple alkenes by a sequential epoxidation, rearrangement, and reduction has also been realized.
Rhodium/tris-binaphthyl chiral monophosphite complexes: Efficient catalysts for the hydroformylation of disubstituted aryl olefins
Carrilho, Rui M.B.,Neves,Loureno, Mirtha A.O.,Abreu, Artur R.,Rosado, Mário T.S.,Abreu, Paulo E.,Eusébio, M. Ermelinda S.,Kollár, László,Bayón, J. Carles,Pereira, Mariette M.
experimental part, p. 28 - 34 (2012/02/04)
A family of threefold symmetry phosphite ligands, P(O-BIN-OR)3 (BIN = 2,2′-binaphthyl; R = Me, Bn, CHPh2, 1-adamantyl), derived from enantiomerically pure (R)-BINOL, was developed. Cone angles within the range 240-270° were calculated for the phosphite ligands, using the computational PM6 Hamiltonian. Their rhodium complexes formed in situ showed remarkable catalytic activity in the hydroformylation of hindered phenylpropenes, under relatively mild reaction conditions, with full chemoselectivity for aldehydes, high regioselectivity, however with low enantioselectivity. The ether substituents at the ligand affected considerably the catalytic activity on the hydroformylation of 1,1- and 1,2-disubstituted aryl olefins. The kinetics of the hydroformylation of trans-1-phenyl-1-propene, using tris[(R)-2′-benzyloxy-1,1′-binaphthyl-2-yl]phosphite as model ligand, was investigated. A first order dependence in the hydroformylation initial rate with respect to substrate and catalyst concentrations was found, as well as a positive order with respect to the partial pressure of H2, and a slightly negative order with respect to phosphite concentration and CO partial pressure.
Highly enantioselective hydroformylation of aryl alkenes with diazaphospholane ligands
Watkins, Avery L.,Hashiguchi, Brian G.,Landis, Clark R.
scheme or table, p. 4553 - 4556 (2009/05/13)
(Chemical Equation Presented) Asymmetric, rhodium-catalyzed hydroformylation of terminal and internal aryl alkenes with diazaphospholane ligands is reported. Under partially optimized reaction conditions, high enantioselectivity (>90% ee) and regioselectivities (up to 65:1 α:β) are obtained for most substrates. For terminal alkenes, both enantioselectivity and regioselectivity are proportional to the carbon monoxide partial pressure, but independent of hydrogen pressure. Hydroformylation of para-substituted styrene derivatives gives the highest regioselectivity for substrates bearing electron-withdrawing substituents. A Hammett analysis produces a positive linear correlation for regioselectivity.
Stereoselective Construction of Acyclic Carbon Chains by a One-Pot Coupling Process Based on Alkenyloxazoline-Titanium Complexes
Mitsui, Kazuhisa,Sato, Takayuki,Urabe, Hirokazu,Sato, Fumie
, p. 490 - 492 (2007/10/03)
A versatile organometallic intermediate, an alkenyloxazoline-titanium complex, has been developed that enables one-pot multicomponent diastereoselective and asymmetric coupling processes to be achieved in a remarkably efficient manner (see scheme).
Pseudoephedrine as a practical chiral auxiliary for the synthesis of highly enantiomerically enriched carboxylic acids, alcohols, aldehydes, and ketones
Myers, Andrew G.,Yang, Bryant H.,Chen, Hou,McKinstry, Lydia,Kopecky, David J.,Gleason, James L.
, p. 6496 - 6511 (2007/10/03)
The use of pseudoephedrine as a practical chiral auxiliary for asymmetric synthesis is described in full. Both enantiomers of pseudoephedrine are inexpensive commodity chemicals and can be N-acylated in high yields to form tertiary amides. In the presence of lithium chloride, the enolates of the corresponding pseudoephedrine amides undergo highly diastereoselective alkylations with a wide range of alkyl halides to afford α-substituted products in high yields. These products can then be transformed in a single operation into highly enantiomerically enriched carboxylic acids, alcohols, aldehydes, and ketones.
Non-destructive Removal of the Bornanesultam Auxiliary in α-Substituted N-Acylbornane-10,2-sultams under Mild Conditions: An Efficient Synthesis of Enantiomerically Pure Ketones and Aldehydes
Oppolzer, Wolfgang,Darcel, Christophe,Rochet, Patrick,Rosset, Stephane,Brabander, Jef De
, p. 1319 - 1337 (2007/10/03)
α-Substituted N-acylbornane-10,2-sultams 6, 9, and 10 can be converted into enantiomerically pure ketones 5, 13, and 14, respectively, via a two-step procedure involving a known mercaptolysis reaction followed by an -mediated coupling of the resulting S-benzyl thioesters with Grignard reagents.Furthermore, enantiomerically pure aldehydes 23 can be obtained from α-substituted N-acylbornane-10,2-sultams 6 via a one-step reduction with (i-Bu)2AlH.No epimerization at the α-chiral center is observed during the cleavage reaction whereby the chiral auxiliary, bornane-10,2-sultam 1 or ent-1, was recovered.By using this methodology, several natural products or precursors thereof can be prepared.
