Online article for Non-subscribers

Pay per view

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact:

Price: ¥ 4,400 (Yen only)
Period: This Article can be accessed for 7 days.

Paper | Regular issue | Vol 100, No. 3, 2020, pp.383-398
Published online, 26th February, 2020
DOI: 10.3987/COM-20-14207
Efficient and Divergent Synthesis of Benzoxazoles and 1,2-Benzisoxazoles from o-Hydroxyaryl Ketoximes

Zhenhua Li,* Guoqiang Jin, Jingjing Qin, Zhiyong Tan, and Jiayu He

*College of Pharmaceutical Sciences, Zhejiang University of Technology, No.18 Chaowang Road, 6th Zhaohui District, Hangzhou, Zhejiang Province 310014, China


A bis(trichloromethyl) carbonate (BTC) / triphenylphosphine oxide (TPPO) system promoting tunable cyclization of a variety of o-hydroxyaryl ketoximes to benzoxazoles and benzisoxazoles was developed. The synthetic switch was enabled by base-free or the use of Et3N. Under base-free conditions, o-hydroxyaryl ketoximes were treated with BTC/TPPO giving corresponding 2-substituted benzoxazoles via cascaded Beckmann rearrangement and intramolecular oxa-cyclization. Analogously, the 3-substituted benzisoxazoles were obtained via intramolecular nucleophilic substitution reactions in the presence of Et3N. This process features mild reaction conditions, high chemoselectivity, and good functional groups tolerance.