Telescoping Reactions with Trifluorodiazoethane-Derived Aza-Wittig Reagents and Allenyl esters - Normandie Université Access content directly
Journal Articles Chemistry - A European Journal Year : 2018

Telescoping Reactions with Trifluorodiazoethane-Derived Aza-Wittig Reagents and Allenyl esters

Fa-Guang Zhang
Yan Zheng
  • Function : Author
Jun-An Ma

Abstract

A telescoping process involving the consecutive addition of four reagents (trifluorodiazoethane, phosphine, allenyl ester, and acetic acid) into a single reactor was developed for the novel functionalization of allenyl esters. First, new phosphazenes derived from trifluorodiazoethane and phosphines were generated and reacted with allenyl esters to give unexpected α‐iminophosphoranes through the creation of C=P, C=N, and C−H bonds at the α‐, β‐, and γ‐carbon atoms, respectively, of the allenyl esters. The α‐iminophosphoranes did not react with aldehydes in a classic Wittig reaction, but instead β‐enamino esters were obtained. The overall sequence of reactions offered a formal hydrohydrazonation of allenyl esters. The method was extended to other related diazo compounds and applied to the preparation of novel 5‐pyrazolone derivatives. Not only is the telescoping process described herein an effective approach for truncating the multistep synthesis, but also each step has been dissected to understand and support the reaction mechanisms.
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Dates and versions

hal-02024538 , version 1 (19-02-2019)

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Fa-Guang Zhang, Jun-Liang Zeng, Yi-Quiang Tian, Yan Zheng, Dominique Cahard, et al.. Telescoping Reactions with Trifluorodiazoethane-Derived Aza-Wittig Reagents and Allenyl esters. Chemistry - A European Journal, 2018, 24 (30), pp.7749-7754. ⟨10.1002/chem.201801171⟩. ⟨hal-02024538⟩
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