624-60-2Relevant articles and documents
La[N(sime3)2]3-catalyzed deoxygenative reduction of amides with pinacolborane. scope and mechanism
Barger, Christopher J.,Dicken, Rachel D.,Weidner, Victoria L.,Motta, Alessandro,Lohr, Tracy L.,Marks, Tobin J.
supporting information, p. 8019 - 8028 (2020/05/27)
Tris[N,N-bis(trimethylsilyl)amide]lanthanum (LaNTMS) is an efficient and selective homogeneous catalyst for the deoxygenative reduction of tertiary and secondary amides with pinacolborane (HBpin) at mild temperatures (25-60 °C). The reaction, which yields amines and O(Bpin)2, tolerates nitro, halide, and amino functional groups well, and this amide reduction is completely selective, with the exclusion of both competing inter- and intramolecular alkene/alkyne hydroboration. Kinetic studies indicate that amide reduction obeys an unusual mixed-order rate law which is proposed to originate from saturation of the catalyst complex with HBpin. Kinetic and thermodynamic studies, isotopic labeling, and DFT calculations using energetic span analysis suggest the role of a [(Me3Si)2N]2La-OCHR(NR′2)[HBpin] active catalyst, and hydride transfer is proposed to be ligand-centered. These results add to the growing list of transformations that commercially available LaNTMS is competent to catalyze, further underscoring the value and versatility of lanthanide complexes in homogeneous catalysis.
Nonracemic betti base as a new chiral auxiliary: Application to total syntheses of enantiopure (2S,6R)-dihydropinidine and (2S,6R)-isosolenopsins
Wang, Xinyan,Dong, Yanmei,Sun, Jianwei,Xu, Xuenong,Li, Rui,Hu, Yuefei
, p. 1897 - 1900 (2007/10/03)
(Chemical Equation Presented) Total syntheses of enantiopure alkaloidal natural products (2S,6R)-dihydropinidine (as hydrochloride) and (2S,6R)-isosolenopsins (as hydrochlorides) were achieved in four steps and in 80-82% total yields by using a synthetic strategy of the formation-cleavage of 1,3-oxazinane. (S)-Betti base was proved to be an excellent chiral auxiliary and a novel Pd/C catalyzed N-debenzylation straightforward to amine hydrochloride was developed in the presence of CH2Cl2.
