Synthesis 2017; 49(07): 1641-1647
DOI: 10.1055/s-0036-1588357
paper
© Georg Thieme Verlag Stuttgart · New York

A Simple and Green Tandem Knoevenagel–Phospha-Michael Reaction for One-Pot Synthesis of 2-Oxindol-3-ylphosphonates Catalyzed by a DABCO-Based Ionic Liquid

Lan-Lan Song
a   National Pesticide Engineering Research Center (Tianjin), State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. of China   Email: xudazhen@nankai.edu.cn
,
Cheng Yang
a   National Pesticide Engineering Research Center (Tianjin), State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. of China   Email: xudazhen@nankai.edu.cn
,
Ya-Qin Yu*
b   Key Laboratory for Water Environment and Resources, Tianjin Normal University, Tianjin, 300387, P. R. of China   Email: yuyaqin@mail.tjnu.edu.cn
,
Da-Zhen Xu*
a   National Pesticide Engineering Research Center (Tianjin), State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. of China   Email: xudazhen@nankai.edu.cn
› Author Affiliations
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Publication History

Received: 23 September 2016

Accepted after revision: 01 November 2016

Publication Date:
06 December 2016 (online)


Abstract

A simple, clean, and efficient approach for the one-pot synthesis of 2-oxindol-3-ylphosphonates has been successfully developed. With 7 mol% loading of the 1,4-diazabicyclo[2.2.2]octane-based ionic liquid catalyst, 2-oxindol-3-ylphosphonates form in good to excellent yields within short times. This tandem reaction involves a phospha-Michael­ addition to the activated alkenes, which form in situ by Knoevenagel­ condensation. The corresponding products are easily separated and purified by simple crystallization. The catalyst can be recycled five times without significant activity loss. This approach is readily amenable to large-scale synthesis.

Supporting Information