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Updated: Apr 17, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Theoretical examination of the S-C-P anomeric effect
Eusebio Juaristi1, Rafael Notario
1Departamento de Química, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional , Apartado Postal 14-740, 07000 Mexico, D. F., México.
Abstract:
Three decades after the discovery of a strong S-C-P anomeric effect in 2-diphenylphosphinoyl-1,3-dithiane (1) and 2-trimethylphosphonium-1,3-dithiane (4), its definitive interpretation is still lacking. The present study reports DFT geometry optimizations of 1-ax, 1-eq, 4-ax, and 4-eq, which do reproduce the S-C-P anomeric effect in 1 and 4, worth 5.45 and 3.08 kcal/mol, respectively (in chloroform solvent). Weinhold's NBO analysis supports the existence of dominant nX → σ*C-Y stereoelectronic interactions that stabilize the axial conformers.
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