Ojha Devi Prasan, Prabhu Kandikere Ramaiah
Department of Organic Chemistry, Indian Institute of Science , Bangalore 560012, Karnataka, India.
Org Lett. 2016 Feb 5;18(3):432-5. doi: 10.1021/acs.orglett.5b03416. Epub 2016 Jan 13.
A ligand controlled selective hydroborylation of alkynes to α- or β-vinylboronates has been developed using a Pd catalyst. The high α-selectivity displayed by this reaction can be switched to furnish β-vinylboronates by altering the ligand from a trialkylphosphine to N-heterocyclic carbene. A variety of terminal alkynes are shown to furnish the corresponding α- or β-vinylboronates in good to excellent selectivity and yield. The mechanistic studies suggest that the solvent is the proton source and bromobenzene functions as an important additive in driving this reaction forward.
已开发出一种使用钯催化剂将炔烃选择性氢硼化生成α-或β-乙烯基硼酸酯的配体控制方法。通过将配体从三烷基膦改为N-杂环卡宾，该反应所显示的高α-选择性可转变为生成β-乙烯基硼酸酯。各种末端炔烃均能以良好至优异的选择性和产率生成相应的α-或β-乙烯基硼酸酯。机理研究表明，溶剂是质子源，溴苯在推动该反应进行中起重要添加剂的作用。
