Synthesis of Axially Chiral Styrenes through Pd-Catalyzed Asymmetric C-H Olefination Enabled by an Amino Amide Transient Directing Group.
Angew Chem Int Ed Engl
; 59(16): 6576-6580, 2020 04 16.
Article
in En
| MEDLINE
| ID: mdl-32011797
ABSTRACT
The atroposelective synthesis of axially chiral styrenes remains a formidable challenge due to their relatively lower rotational barriers compared to the biaryl atropoisomers. Herein, we describe the construction of axially chiral styrenes through PdII -catalyzed atroposelective C-H olefination, using a bulky amino amide as a transient chiral auxiliary. Various axially chiral styrenes were produced with good yields and high enantioselectivity (up to 95 % yield and 99 % ee). Carboxylic acid derivatives of the resulting axially chiral styrenes showed superior enantiocontrol over the biaryl counterparts in CoIII -catalyzed enantioselective C(sp3 )-H amidation of thioamide. Mechanistic studies suggest that C-H cleavage is the enantioselectivity-determining step.
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MEDLINE
Language:
En
Year:
2020
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Article