Journal Article

Pivotal Synthesis of Tetrasubstituted Epoxides from Ketones and α‐Halo B/Si Ylides with Understanding of the Activation Modes

Wilkinson, Stanley, Morán‐González, Lucia, Rodríguez, Marcos, Maseras, Feliu, Salvadó, Oriol, Apaloo‐Messan, Edmond, Dominguez‐Molano, Paula, Fernández, Elena, Tarifa, Luis

2026

Overview

The epoxidation of ketones with α‐monohalo borylsilylmethane reagents renders tetrasubstituted epoxides, opening a new reactive pathway by supression of Boron‐Wittig or Peterson olefination pathways. This method enables the preparation of novel 1,1,2,2‐tetrasubstituted borosilylepoxides with intrinsic control of the diastereoselectivity. A mechanism, based on density functional theory calculations, has been postulated analyzing the role of the α‐iodo B, Si‐ylide in the cyclization pathway. Complementarily, enolates generated from ketones can also interact with the α‐monohalo diborylsilylmethane reagents to acceed the 1,1,2,2‐tetrasubstituted borosilylepoxides. The versatility of these entities has been demonstrated through postfunctionalization reactions. The preparation of diastereoselective 1,1,2,2‐tetrasubstituted borosilylepoxides is described, involving the epoxidation of ketones with α‐monohalo borylsilylmethane reagents. The nature of the ambiphilic reagent suppressed the Boron‐Wittig olefination. Density functional theory calculations analyzed the role of α‐iodo B, Si‐ylide in the epoxidation concluding that the highest occupied molecular orbital and the natural population analysis atomic charge on the carbon justify its exceptional reactivity.

• Publisher: Wiley-VCH
• Subject: boron ylides / density functional theory calculations / epoxidation / mechanisms / stereoselectivity