Synthesis 2016; 48(12): 1892-1901
DOI: 10.1055/s-0035-1561590
special topic
© Georg Thieme Verlag Stuttgart · New York

Acid-Catalyzed Ring-Opening Cyclization of Spirocyclopropanes for the Construction of a 2-Arylbenzofuran Skeleton: Total Synthesis of Cuspidan B

Hisanori Nambu*
Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama 930-0194, Japan   Email: nambu@pha.u-toyama.ac.jp   yakura@pha.u-toyama.ac.jp
,
Naoki Ono
Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama 930-0194, Japan   Email: nambu@pha.u-toyama.ac.jp   yakura@pha.u-toyama.ac.jp
,
Takayuki Yakura*
Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama 930-0194, Japan   Email: nambu@pha.u-toyama.ac.jp   yakura@pha.u-toyama.ac.jp
› Author Affiliations
Further Information

Publication History

Received: 30 January 2016

Accepted after revision: 01 March 2016

Publication Date:
05 April 2016 (online)


Abstract

Acid-catalyzed ring-opening cyclization of cyclohexane-1,3-dione-2-spirocyclopropanes under metal-free conditions proceeded smoothly at room temperature to provide 2-aryl-3,5,6,7-tetrahydro-1-benzofuran-4(2H)-ones in excellent yields without the formation of 3-substituted isomers. The obtained product was converted into a 2-arylbenzofuran derivative via a synthetically useful 2-aryl-2,3-dihydrobenzofuran intermediate. Furthermore, the first total synthesis of cuspidan B was achieved by using the present method.

Supporting Information