@article{cunha_kascheres_2000,  title={On the reactivity of triphenylphosphoranylidenesuccinic anhydride with nitrogen nucleophiles: a new synthetic route to nitrogen-containing phosphonium salts},  volume={11},  ISSN={0103-5053},  url={https://doi.org/10.1590/S0103-50532000000500015},  DOI={10.1590/S0103-50532000000500015},  number={5},  journal={Journal of the Brazilian Chemical Society},  publisher={Sociedade Brasileira de Química},  author={Cunha, Silvio and Kascheres, Albert},  year={2000},  month={Sep},  pages={525–529} }