Highly Site Selective Formal [5+2] and [4+2] Annulations of Isoxazoles with Heterosubstituted Alkynes by Platinum Catalysis: Rapid Access to Functionalized 1,3-Oxazepines and 2,5-Dihydropyridines
作者:Wen-Bo Shen、Xin-Yu Xiao、Qing Sun、Bo Zhou、Xin-Qi Zhu、Juan-Zhu Yan、Xin Lu、Long-Wu Ye
DOI:10.1002/anie.201610042
日期:2017.1.9
Platinum‐catalyzed formal [5+2] and [4+2] annulations of isoxazoles with heterosubstituted alkynes enabled the atom‐economical synthesis of valuable 1,3‐oxazepines and 2,5‐dihydropyridines, respectively. Importantly, this Pt catalysis not only led to unique reactivity dramatically divergent from that observed under Au catalysis, but also proceeded via unprecedented α‐imino platinum carbene intermediates
铂催化异恶唑与杂取代炔烃的正式[5 + 2]和[4 + 2]环空反应分别实现了经济的合成有价值的1,3-氧杂氮杂和2,5-二氢吡啶。重要的是,这种Pt催化不仅导致与Au催化下观察到的独特反应性显着不同,而且还通过前所未有的α-亚氨基铂卡宾中间体进行了反应。