This report describes the direct synthesis of dihydro-pyrrolo-pyrazole heterocycles from allylic azides and methyl vinyl sulfone. The product results from a complex cascade reaction that is operationally straightforward, with aromatization being the result of a concomitant elimination step. A variety of azides could participate in this reaction (12 examples) and the isolated yields of the desired product ranged from 51%−72%. Lastly the ethylene sulfone group could be removed by heating the product in pyrrolidine.
Bibliographical noteFunding Information:
En-chih Liu, Margaret Clapham, and Dr. Victor Young Jr. are thanked for their assistance with X-ray crystallography. This research was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number R35GM124718. We also acknowledge NIH Shared Instrumentation Grant #S10OD011952. A.S.C. gratefully acknowledges support from the Wayland E. Noland Fellowship and UMN Doctoral Dissertation Fellowship.
© 2021 Elsevier Ltd
- Cascade reaction
- Vinyl sulfone
PubMed: MeSH publication types
- Journal Article