Soto M, Soengas RG, Silva AMS, Gotor-Fernández V, Rodríguez-Solla H. Temperature-Controlled Stereodivergent Synthesis of 2,2'-Biflavanones Promoted by Samarium Diiodide.
Chemistry 2019;
25:13104-13108. [PMID:
31361369 DOI:
10.1002/chem.201902927]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/29/2019] [Indexed: 12/11/2022]
Abstract
In this work, the first example of a radical stereodivergent reaction directed towards the stereoselective synthesis of both (R*,R*)- and (R*,S*)-2,2'-biflavanones promoted by samarium diiodide is reported. Control experiments showed that the selectivity of this reaction was exclusively controlled by the temperature. It was possible to generate a variety of 2,2'-biflavanones bearing different substitution patterns at the aromatic ring in good-to-quantitative yields, being both stereoisomers of the desired compounds obtained with total or high control of selectivity. A mechanism that explains both the generation of the corresponding 2,2'-biflavanones and the selectivity is also discussed. The structure and stereochemistry determination of each isomer was unequivocally elucidated by single-crystal X-ray diffraction experiments.
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