σ2P,O-Hybrid Ligands: Synthesis of the First 4-Hydroxy-1,3-benzazaphospholes by ortho-Lithiation of m-Amidophenyl Diethyl Phosphates.

Autor: Aluri, Bhaskar R., Shah, Kirti, Gupta, Neelima, Fomina, Olga S., Yakhvarov, Dmitry G., Ghalib, Mohammed, Jones, Peter G., Schulzke, Carola, Heinicke, Joachim W.
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Zdroj: European Journal of Inorganic Chemistry; Dec2014, Vol. 2014 Issue 34, p5958-5968, 11p
Abstrakt: The m-phosphorylanilides 2 are available from anilides 1 by the Atherton-Todd reaction; the selective ortho-lithiation of the o′-methyl-protected phosphorylpivalanilide 2b with tBuLi proceeded in high yield in the presence of ClSiMe3. The ortho-lithiation is followed by rapid 1,3-migration of the PO3Et2 group to yield the phosphonoanilide cis/ trans- 3b. This compound mainly reacts with excess LiAlH4 by reductive cyclization to form the 4-hydroxy-1 H-1,3-benzazaphosphole 6. The lithiation of the o′-unprotected phosphorylpivalanilide 2a with LDA was unselective and led to 3a and 4a in low yields, whereas additional ortho-lithiation of the benzoyl group occurred for the lithiation of the o′-protected phosphonobenzanilide 2c with tBuLi/LDA to give 7 in rather low yield. The reduction of crude 7 led to (benzylamino)phenol 8 and the 4-hydroxy-1 H-1,3-benzazaphosphole 9 as a minor product. The properties, NMR spectroscopy data, and crystal structures of 5b, 6, and 8 are reported. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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