825-56-9Relevant articles and documents
General α-Amino 1,3,4-Oxadiazole Synthesis via Late-Stage Reductive Functionalization of Tertiary Amides and Lactams**
Dixon, Darren J.,Matheau-Raven, Daniel
, p. 19725 - 19729 (2021)
An iridium-catalyzed reductive three-component coupling reaction for the synthesis of medicinally relevant α-amino 1,3,4-oxadiazoles from abundant tertiary amides or lactams, carboxylic acids, and (N-isocyanimino) triphenylphosphorane, is described. Proceeding under mild conditions using (3)2) and tetramethyldisiloxane to access the key reactive iminium ion intermediates, a broad range of α-amino 1,3,4-oxadiazole architectures were accessed from carboxylic acid feedstock coupling partners. Extension to α-amino heterodiazole synthesis was readily achieved by exchanging the carboxylic acid coupling partner for C-, S-, or N-centered Br?nsted acids, and provided rapid and modular access to these desirable, yet difficult-to-access, heterocycles. The high chemoselectivity of the catalytic reductive activation step allowed late-stage functionalization of 10 drug molecules, including the synthesis of heterodiazole-fused drug–drug conjugates.
Copper-Catalyzed Enantioconvergent Cross-Coupling of Racemic Alkyl Bromides with Azole C(sp2)?H Bonds
Chang, Xiao-Yong,Chen, Ji-Jun,Gu, Qiang-Shuai,Jiang, Sheng-Peng,Li, Zhong-Liang,Liu, Lin,Liu, Xiao-Dong,Liu, Xin-Yuan,Su, Xiao-Long,Wang, Fu-Li,Yang, Chang-Jiang,Ye, Liu
supporting information, p. 380 - 384 (2020/10/30)
The development of enantioconvergent cross-coupling of racemic alkyl halides directly with heteroarene C(sp2)?H bonds has been impeded by the use of a base at elevated temperature that leads to racemization. We herein report a copper(I)/cinchona-alkaloid-derived N,N,P-ligand catalytic system that enables oxidative addition with racemic alkyl bromides under mild conditions. Thus, coupling with azole C(sp2)?H bonds has been achieved in high enantioselectivity, affording a number of potentially useful α-chiral alkylated azoles, such as 1,3,4-oxadiazoles, oxazoles, and benzo[d]oxazoles as well as 1,3,4-triazoles, for drug discovery. Mechanistic experiments indicated facile deprotonation of an azole C(sp2)?H bond and the involvement of alkyl radical species under the reaction conditions.
Ligand-Enabled Palladium-Catalyzed Through-Space C?H Bond Activation via a Carbopalladation/1,4-Pd Migration/C?H Functionalization Sequence
Chen, Su,Ranjan, Prabhat,Ramkumar, Nagarajan,Van Meervelt, Luc,Van der Eycken, Erik V.,Sharma, Upendra K.
supporting information, p. 14075 - 14079 (2020/10/12)
We report, herein, a palladium-catalyzed cascade comprising carbopalladation, 1,4-Pd-migration and C(sp2)?C(sp2) bond formation to construct a variety of bis-heterocyclic frameworks in a single operational step. The methodology provi
