Metal-Free Catalytic Reduction of α,β-Unsaturated Esters by 1,3,2-Diazaphospholene and Subsequent C–C Coupling with Nitriles
作者:Che Chang Chong、Bin Rao、Rei Kinjo
DOI:10.1021/acscatal.7b01338
日期:2017.9.1
tautomerizes to saturated esters, while the P–O bond cleavage by HBpin via a formal σ-bond metathesis affords boryl enolate intermediate. The latter could undergo a further coupling reaction with nitriles to form substituted amino diesters or 1,3-imino esters, depending on α,β-unsaturated ester substrates. These catalytic reactions can also be performed in a one-pot manner, illustrating a protocol for metal-free
1,3,2-二氮杂磷腈1催化α,β-不饱和酯的共轭转移氢化以及1,4-氢硼化。两种方法的起始步骤都包括α,β-不饱和酯的1,4-氢磷酸化,以得到次膦酰基烯醇醚。氨硼烷随后切断了次膦酰基烯醇醚中的P–O键(AB)生成一个互变异构体成饱和酯的烯醇中间体,而HBpin通过正式的σ键复分解通过HB的P–O键裂解,提供了烯醇硼酸酯中间体。取决于α,β-不饱和酯底物,后者可与腈进一步进行偶联反应以形成取代的氨基二酯或1,3-亚氨基酯。这些催化反应也可以一锅法进行,说明了无金属催化C-C键构建的方案。