Synthesis, Structure, and Reactivity of N-Benzoyl Iminophosphoranes Ortho Lithiated at the Benzoyl Group
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- 作者：David Aguilar ; Ignacio Fernndez ; Luciano Cuesta ; Vctor Yaez-Rodrguez ; Tatiana Soler ; Rafael Navarro ; Esteban P. Urriolabeitia ; Fernando Lpez Ortiz
- 刊名：Journal of Organic Chemistry
- 出版年：2010
- 出版时间：October 1, 2010
- 年：2010
- 卷：75
- 期：19
- 页码：6452-6462
- 全文大小：1049K
- 年卷期：v.75,no.19(October 1, 2010)
- ISSN：1520-6904
文摘
Ortho lithiation of N-benzamido-P,P,P-triaryliminophosphoranes through deprotonation with alkyllithium bases was achieved with ortho-C═O and ortho-P═N chemoselectivity. However, the synthetic scope of these processes was rather limited. Ortho-lithiated N-benzamido-P,P,P-triphenyliminophosphorane 8 was efficiently prepared via lithium/halogen exchange of the corresponding ortho-brominated precursor with s-BuLi in THF at −90 °C. The reaction of 8 with a variety of electrophiles provides an easy and mild method for the regioselective synthesis of ortho-modified iminophosphoranes via C−C (alkylation and hydroxyalkylation) and C−X (X = I, Si, P, Sn, and Hg) bond-forming reactions. NMR characterization of 8 in THF solution showed that 8 exists as an equilibrium mixture of one monomer and two dimers. The Li atoms of these species become members of five-membered rings through chelation by the ortho-metalated carbon and the carbonyl oxygen. The dimers differ in the relative orientation of the two chelates with respect to the plane defined by the C2Li2 core. The equilibrium between all species is established by splitting the dimers into monomers and subsequent recombination with formation of a different dimer.