Preparative Synthesis via Continuous Flow of 4,4,5,5-Tetramethyl-2-(3-trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane: A General Propargylation Reagent
文摘
A scalable process for the preparation of 4,4,5,5-tetramethyl-2-(3-trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane from trimethylsilylpropyne, isopropyl pinacol borate, and n-butyllithium is described. Problems associated with implementing a typical aqueous workup and batch process into production due to borolane 鈥渁te鈥?equilibration and protonolysis are presented. To address these issues, a continuous-flow and distillation process was developed which efficiently produced 297 kg of the key propargylation reagent.