374729-55-2Relevant articles and documents
Easily accessible and highly tunable bisphosphine ligands for asymmetric hydroformylation of terminal and internal alkenes
Xu, Kun,Zheng, Xin,Wang, Zhiyong,Zhang, Xumu
, p. 4357 - 4362 (2014/05/06)
An efficient methodology for synthesizing a small library of easily tunable and sterically bulky ligands for asymmetric hydroformylation (AHF) has been reported. Five groups of alkene substrates have been tested with excellent conversions, moderate-to-excellent regio- and enantioselectivities. Among the best result of the reported literature, application of ligand 1 c in the highly selective AHF of the challenging substrate 2,5-dihydrofuran yielded almost one isomer in up to 99 % conversion along with enantiomeric excesses (ee) of up to 92 %. Highly enantioselective AHF of dihydropyrrole substrates is achieved using the same ligand, with up to 95 % ee and up to >1:50 β-isomer/α- isomer ratio. The simpler the better! An efficient method for the easy and tunable synthesis of a series of asymmetric hydroformylation (AHF) ligands from low-cost, commercially available starting materials has been reported. These ligands can give excellent conversions and moderate to excellent regio- and enantioselectivities for a broad range of mono- and disubstituted alkenes with a low catalyst loading (substrate-to-catalyst ratios (S/C) of 1000:1 to 3000:1).
Optimization of 1,4-diazepan-2-one containing dipeptidyl peptidase IV inhibitors for the treatment of type 2 diabetes
Liang, Gui-Bai,Qian, Xiaoxia,Feng, Dennis,Biftu, Tesfaye,Eiermann, George,He, Huaibing,Leiting, Barbara,Lyons, Kathy,Petrov, Aleksandr,Sinha-Roy, Ranabir,Zhang, Bei,Wu, Joseph,Zhang, Xiaoping,Thornberry, Nancy A.,Weber, Ann E.
, p. 1903 - 1907 (2008/02/04)
Following the discovery of N-acyl-1,4-diazepan-2-one as a novel pharmacophore for potent and selective DPP-4 inhibitors, optimization of this new lead with different substitution on the seven-membered ring resulted in several highly potent and selective,
Enantiospecific synthesis of the (9S,18R)-diastereomer of the leukocyte adhesion inhibitor cyclamenol A
Nazare, Marc,Waldmann, Herbert
, p. 3363 - 3376 (2007/10/03)
Cyclamenol A is one of the very few non-carbohydrate and non-peptide natural products that inhibit leukocyte adhesion to endothelial cells. We report on the first enantioselective total synthesis of the (9S, 18R)-diastereomer of this macrocyclic polyene lactam. Key elements of the synthesis are i) the synthesis of the required chiral building blocks by employing readily accessible building blocks from the chiral pool, that is, (S)-malic acid and (R)-hydroxyisobutyric acid, ii) assembly of a linear polyene precursor by means of Wittig and Horner olefination reactions as key C-C bond-forming transformations, iii) ring closure by means of a vanadium-mediated pinacolisation reaction and iv) conversion of the generated cis-diol into a (Z)-olefin to complete the entire polyene system of the natural product. Attempts to close the macrocyclic ring by a macrolactamisation, a double Stille coupling or direct olefination in a McMurry reaction failed. Crucial to the successful completion of the synthesis was the correct orchestration of the final steps. It was necessary to first deprotect the intermediate formed after macrocycle formation and to generate the sensitive heptaene system in the last step by means of a Corey-Hopkins sequence.
