Stereoselective Synthesis of Complex Polyenes through Sequential α-/ß-C-H Functionalization of trans-Styrenes.
Angew Chem Int Ed Engl
; 63(12): e202315273, 2024 Mar 18.
Article
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| MEDLINE
| ID: mdl-38217399
ABSTRACT
Sequential C-H functionalization of molecules containing multiple C-H bonds can efficiently lead to structural diversity. Herein we present the first chelation-assisted sequential α-/ß-C-H functionalization of E-styrenes with simple alkenes and alkynes in excellent regio- and stereo-selectivity. The process involves α C-H functionalization by six-membered exo-cyclopalladation to result in tri- and tetrasubstituted 1,3-dienes and ß C-H functionalization through seven-membered endo-cyclopalladation to produce tetra- and pentasubstituted 1,3,5-trienes in up to 97 % yield with up to >99/1 E/Z selectivity, both enabled by the chelation assistance of pyrazinamide. The protocol is demonstrated to be widely applicable, tolerant to a wide range of functional groups and bioactive fragments, and suitable for gram-scale synthesis as well as one-pot and two step preparation of trienes. Mechanistic experiments and density functional theory (DFT) calculations were performed to elucidate the selectivity and reactivity.
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MEDLINE
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Año:
2024
Tipo del documento:
Article
País de afiliación:
China