Desroches J, Tremblay A, Paquin JF. Racemic and enantioselective metal-catalyzed synthesis of SF
5-containing diarylmethanols.
Org Biomol Chem 2018;
14:8764-8780. [PMID:
27714227 DOI:
10.1039/c6ob01663d]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The racemic and enantioselective metal-catalyzed addition of arylboronic acids to 4- and 3-(pentafluorosulfur)benzaldehydes is reported. The racemic synthesis was accomplished using a Pd-based system and a wide range of arylboronic acids could be used, resulting in yields of 42 to 98% of the corresponding SF5-containing diarylmethanols. A ruthenium-based system, along with (R,R)-Me-BIPAM as the chiral ligand, was investigated and optimized for the enantioselective version. In this case, while the chiral SF5-containing diarylmethanols were generally obtained in good yields (up to 94%) and enantioselectivities (up to 98% ee), limitations were also observed. For instance, 4-(pentafluorosulfur)benzaldehyde generally provided slightly better yields than 3-(pentafluorosulfur)benzaldehyde. In addition, lower yields and enantioselectivities were observed when using either 4- and 3-substituted arylboronic acids bearing electron-withdrawing (e.g., CO2Et, NO2, CF3) or 2-substituted arylboronic acids (regardless of the nature of the substituent). Overall, the SF5-containing diarylmethanols described herein represent novel and potentially useful fluorinated building blocks for the synthesis of biologically active compounds.
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