N-Heterocyclic Carbene-Catalyzed Double Michael Addition: Stereoselective Synthesis of Spirofluorenes and Multisubstituted Indanes
作者:Fen Xing、Ze-Nan Feng、Ying Wang、Guang-Fen Du、Cheng-Zhi Gu、Bin Dai、Lin He
DOI:10.1002/adsc.201701269
日期:2018.4.17
The strong Brønsted basic character of N‐heterocyclic carbenes (NHCs) has been used to promote the cascade doubleMichaeladdition between fluorenes and dienones. Under catalyst loadings of 1–5 mol% of NHC, fluorene reacts with divinyl ketones (DVKs) to afford anti‐spirofluorene compounds in high yields. However, when benzenedi(enones) were employed as Michael acceptors in the presence of 10 mol% of