Ban, X., Fan, Y., Kha, T.-K., Lee, R., Kee, C. W., Jiang, Z., & Tan, C.-H. (2021). Pentanidium-Catalyzed Direct Assembly of Vicinal All-Carbon Quaternary Stereocenters through C(sp 3 )-C(sp 3 ) Bond Formation. CCS Chemistry, 3(10), 2192–2200. doi:10.31635/ccschem.021.202101013
Abstract:
The stereoselective construction of vicinal all-carbon quaternary stereocenters has long been a formidable synthetic challenge. Direct asymmetric coupling of a tertiary carbon nucleophile with a tertiary carbon electrophile is the most straightforward approach, but it is sterically and energetically disfavored. Herein, we describe a catalytic asymmetric substitution, where racemic tertiary bromides coupled directly with racemic secondary or tertiary carbanion, creating a series of congested C(sp3)–C(sp3) bonds, including isolated all-carbon quaternary stereocenters, vicinal tertiary/all-carbon quaternary stereocenters and vicinal all-carbon quaternary stereocenters. Using pentanidium as a catalyst, this double stereoconvergent process afforded substituted products in good enantioselectivities and diastereoselectivities.
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the Nanyang Technological University - Tier 1
Grant Reference no. : RG1/19
This research / project is supported by the Nanyang Technological University - Tier 1
Grant Reference no. : RG2/20
This research / project is supported by the Ministry of Education (Singapore) - Tier 2
Grant Reference no. : MOE2019-T2-1-091
University of Wollongong (VC Fellowship) and the Australian Research Council (DECRA DE210100053).