posted on 2018-02-19, 00:00authored byMiao Wang, Bo-Cheng Tang, Jia-Chen Xiang, Yan Cheng, Zi-Xuan Wang, Jin-Tian Ma, Yan-Dong Wu, An-Xin Wu
An efficient base-promoted
C(sp3)–H bond functionalization
strategy for the synthesis of multisubstituted chromans from the formal
[3+3] cycloaddition of benzo[c]oxepines and electron-rich
phenols has been developed. The corresponding 4H-chromenes
can be easily obtained in excellent yields by simple filtration from
chromans. Preliminary mechanistic studies indicate that the C–O
bond cleavage is the key step for the C(sp3)–H bond
functionalization and that this reaction could have occurred through
tandem C–O bond cleavage/Michael addition/annulation reactions.