Divergent Metal-Free [4 + 2] Cascade Reaction of 1-Indanylidenemalononitrile with 3-Benzylidenebenzofuran-2(3 H)-one: Access to Spiro-dihydrofluorene-benzofuranone and Axially Chiral Fluorenylamine-phenol Derivatives

Ran Li; Lei Yao; Yan-Bo Wang; Jun-Yan Zhu; Lixiong Zhang; Ji-Ya Fu; Chuan-Bao Zhang; Lili Zhao

doi:10.1021/acs.orglett.1c01510

Divergent Metal-Free [4 + 2] Cascade Reaction of 1-Indanylidenemalononitrile with 3-Benzylidenebenzofuran-2(3 H)-one: Access to Spiro-dihydrofluorene-benzofuranone and Axially Chiral Fluorenylamine-phenol Derivatives

Org Lett. 2021 Aug 6;23(15):5611-5615. doi: 10.1021/acs.orglett.1c01510. Epub 2021 Jul 9.

Authors

Ran Li¹, Lei Yao², Yan-Bo Wang¹, Jun-Yan Zhu¹, Lixiong Zhang³, Ji-Ya Fu¹, Chuan-Bao Zhang⁴, Lili Zhao²

Affiliations

¹ Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China.
² Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
³ College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
⁴ School of Pharmacy, Zhengzhou Railway Vocational & Technical College, Zhengzhou 450052, China.

PMID: 34240601
DOI: 10.1021/acs.orglett.1c01510

Abstract

An efficient cascade reaction of 1-indanylidenemalononitrile with 3-benzylidenebenzofuran-2(3H)-one divergently promoted by DABCO or chiral organocatalyst was developed under mild reaction conditions, and various spiro-dihydrofluorene-benzofuranones were produced in gratifying results, respectively. It is worth noting that both the spiro and axially chiral products can be obtained by tuning the reaction conditions. The mechanism of the transformation was also studied by quantum chemical calculations.