This document discusses the development of a tandem reaction involving carbanion-induced ring-opening of a three-membered ring followed by a [3+2] annulation. Specifically, it involves the [3+2] annulation of tosylmethylcyclopropane mediated by carbanions, where intermediates of the reaction were isolated. The document references several other papers on related topics like donor-acceptor cyclopropanes, Lewis acid-catalyzed cyclopropane/aldehyde cycloadditions, and oxyanion-induced ring opening of cyclopropanes.

1. カルバニオンによって誘起される三員環の開環を
伴うタンデム型環化反応の開発
広島大学大学院医歯薬保健学研究院
西尾 卓哉，近藤 泰博，佐々木 道子，武田 敬

2. Reissig, H.-U. Topics in Current Chemistry, 1988, 144, 74-135.
Schneider, T. F.; Kaschel, J.; Werz, D. B. Angew. Chem. Int. Ed., 2014, 53, 5504–5523.
Grover, H. K.; Emmett, M. R.; Kerr, M. A. Org. Biomol. Chem ., 2015, 13, 655–671.
D (Donor): OR, SR, NR2 etc.
A (Acceptor): CO2R, NO2, CN etc.
Donor-Acceptor Cyclopropanes
1,3-dipolar synthon
Pohlhaus, P. D.; Johnson, J. S. J. Org. Chem. 2005, 1057–1059.
Lewis Acid-Catalyzed Cyclopropane/Aldehyde Cycloadditions

3. Carbanion Induced [3 + 2] Annulation of Donor-Acceptor Cyclopropanes
Kunkel, E.; Reichelt, I.; Reissig, H. U. Liebigs Ann. Chem. 1984, 802.
Oxyanion-Induced Ring Opening of Cyclopropane

4. Ring Opening of Tosylmethylcyclopropane
[3 + 2] Annulation of Tosylmethylcyclopropane

5. [3 + 2] Annulation of Tosylmethylcyclopropane

6. Isolation of Intermediates of [3 + 2] Annulation of Tosylmethylcyclopropane

11. * 1. LiHMDS, –80 °C, 2. Ylidenmalonate was added after treatment of starting material with LiHMDS

12. Summary
1,3-dipolar synthon
Sasaki, M.; Kondo, Y.; Nishio, T.; Takeda, K. Org. Lett. 2016, 18, 3858–3861.