114653-19-9Relevant articles and documents
Rhodium-Catalysed Hydroboration of Terminal Alkynes Using Pinacolborane Promoted by Tri(2-furyl)phosphine
Wang, Kongchen,Bates, Roderick W.
, p. 2749 - 2752 (2017)
Tri(2-furyl)phosphine is a superior ligand to triphenylphosphine in the rhodium-catalysed hydroboration of alkynes with pinacolborane to yield alkenylboronates. In general the reactions are faster and the products are cleaner.
Enantioselective Construction of Quaternary Stereogenic Centers by the Addition of an Acyl Anion Equivalent to 1,3-Dienes
Adamson, Nathan J.,Malcolmson, Steven J.,Nguyen, Andrew L.,Park, Sangjune,Zhou, Pengfei
supporting information, (2020/03/04)
We report the enantioselective formation of quaternary stereogenic centers by the intermolecular addition of malononitrile, an acyl anion equivalent, and related pronucleophiles to several 1,3-disubstituted acyclic 1,3-dienes in the presence of a Pd-PHOX catalyst. Products are obtained in up to 88% yield and 99:1 er and in most cases are formed as a single regioisomer. The products' malononitrile unit undergoes oxidative functionalization to afford β,γ-unsaturated carbonyls bearing internal olefins and α-quaternary stereogenic centers.
Aluminum Hydroxide Secondary Building Units in a Metal-Organic Framework Support Earth-Abundant Metal Catalysts for Broad-Scope Organic Transformations
Feng, Xuanyu,Ji, Pengfei,Li, Zhe,Drake, Tasha,Oliveres, Pau,Chen, Emily Y.,Song, Yang,Wang, Cheng,Lin, Wenbin
, p. 3327 - 3337 (2019/03/26)
The intrinsic heterogeneity of alumina (Al2O3) surface presents a challenge for the development of alumina-supported single-site heterogeneous catalysts and hinders the characterization of catalytic species at the molecular level as well as the elucidation of mechanistic details of the catalytic reactions. Here we report the use of aluminum hydroxide secondary building units (SBUs) in the MIL-53(Al) metal-organic framework (MOF) with the formula Al(μ2-OH)(BDC) (BDC = 1,4-benzenedicarboxylate) as a uniform and structurally defined functional mimic of Al2O3 surface for supporting Earth-abundant metal (EAM) catalysts. The μ2-OH groups in MIL-53(Al) SBUs were readily deprotonated and metalated with CoCl2 and FeCl2 to afford MIL-53(Al)-CoCl and MIL-53(Al)-FeCl precatalysts which were characterized by powder X-ray diffraction, nitrogen sorption, elemental analysis, density functional theory, and extended X-ray fine structure spectroscopy. Activation with NaBEt3H converted MIL-53(Al)-CoCl to MIL-53(Al)-CoH which effectively catalyzed hydroboration of alkynes and nitriles and hydrosilylation of esters. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of AlIII and CoII centers in MIL-53(Al)-CoH while deuterium labeling studies suggested σ-bond metathesis as a key step for the MIL-53(Al)-CoH-catalyzed addition reactions. MIL-53(Al)-FeCl competently catalyzed oxidative Csp3-H amination and Wacker-type alkene oxidation. XANES analysis revealed the oxidation of FeII to FeIII centers in the activated MIL-53(Al)-FeCl catalyst and suggested that oxidative Csp3-H amination occurs via the formation of FeIII-OtBu species by single electron transfer between FeII centers in MIL-53(Al)-FeCl and (tBuO)2 with concomitant generation of 1 equiv of tBuO· radical, C-H activation through hydrogen atom abstraction to generate alkyl radicals, protonation of FeIII-OtBu by aniline to generate MIL-53(Al)-FeIII-anilide, and finally C-N coupling between the FeIII-anilide and alkyl radical to form the Csp3-H amination product and regenerate the FeII catalyst. These highly active single-site MOF-based solid catalysts were readily recovered and reused up to five times without significant decrease in catalytic activity. This work thus demonstrates the great potential of using the aluminum hydroxide SBUs in MOFs to support EAM catalysts for important organic transformations.
