6006-75-3Relevant articles and documents
Asymmetric Desymmetrization of Oxetanes for the Synthesis of Chiral Tetrahydrothiophenes and Tetrahydroselenophenes
Zhang, Renwei,Guo, Wengang,Duan, Meng,Houk,Sun, Jianwei
supporting information, p. 18055 - 18060 (2019/11/13)
Chiral tetrahydrothiophenes and tetrahydroselenophenes are highly useful structural units. Described here is a new catalytic asymmetric approach for their synthesis. With a suitable chiral Br?nsted acid catalyst, an oxetane desymmetrization by a well-positioned internal sulfur or selenium nucleophile proceeded efficiently to generate all-carbon quaternary stereocenters with excellent enantioselectivities. Taming the sulfur and selenium nucleophile in the form of a thioester and selenoester, respectively, is crucial to the success of this work. This approach also allows the facile synthesis of chiral tetrahydrothiopyrans. Mechanistic studies, including DFT calculations, suggested an intramolecular acyl-transfer pathway. Utilities of the chiral products are also demonstrated.
Modular, catalytic enantioselective construction of quaternary carbon stereocenters by sequential cross-coupling reactions
Potter, Bowman,Edelstein, Emma K.,Morken, James P.
, p. 3286 - 3289 (2016/07/13)
The catalytic Suzuki-Miyaura cross-coupling with chiral γ,γ-disubstituted allylboronates in the presence of RuPhos ligand occurs with high regioselectivity and enantiospecificity, furnishing nonracemic compounds with quaternary centers. Mechanistic experiments suggest that the reaction occurs by transmetalation with allyl migration, followed by rapid reductive elimination.
Enantioselective construction of quaternary stereogenic centers from tertiary boronic esters: Methodology and applications
Sonawane, Ravindra P.,Jheengut, Vishal,Rabalakos, Constantinos,Larouche-Gauthier, Robin,Scott, Helen K.,Aggarwal, Varinder K.
supporting information; experimental part, p. 3760 - 3763 (2011/06/22)
Pin it down: A range of substrates that bear versatile functional groups with quaternary stereogenic centers have been prepared with very high enantioselectivity from tertiary boronic esters (see scheme; Cb=N,N-diisopropylcarbamoyl, pin=pinacolato). The preparation of allylboronic esters bearing contiguous quaternary and tertiary stereogenic centers, and applications to natural product synthesis are also reported.
