1,3‐Phosphorotropic rearrangement of pyridyl phosphates to hydroxypyridyl phosphonates

Abstract

The lithium diisopropylarnide (LDA) induced regioselective 1,3-reawungement of 3-and 2-pyridyl phosphates into the corresponding 3-hydroxy-4-pyr~dyl-and 2-hydroxy-3-pyridylphosphonates has been observed and investigated. The rearrangement is proposed as a useful method for a directed introduction of a phosphoryl group into a hydroxypyridine nucleus.

Comprehensive Overview of Progress in Functionalization of 2‐Pyridone and 2, 4 ‐Dihydroxy Pyridine: Key Constituents of Vital Natural Products

“…Onysko et al . developed synthesis of C‐ phosphonylated pyridines induced by Lithium diisopropylamide (LDA) [154] . The reaction consisted of forming 2‐pyridyl phosphate from 2‐pyridone (83) and diethoxy phosphoryl chloride.…”

“…Onysko et al developed synthesis of C-phosphonylated pyridines induced by Lithium diisopropylamide (LDA). [154] The reaction consisted of forming 2-pyridyl phosphate from 2pyridone (83) and diethoxy phosphoryl chloride. (181) It was followed by formation of 3-phosphonylated 2-pyridone product (183) by [1,3-O-C]-rearrangement of (182) (Scheme 55).…”

C‐Phosphorylated pyrazoles. Reaction of N‐methyl‐ and N‐phenylpyrazoles with phosphorus(III) halides

“…From the dibromophosphines 4-6 obtained, we synthesized dioxy and diaminophosphines by usual methods. Similarly to some other alkoxy heteroarylphosphines [22], compound 14 is unstable, probably because of alkylation.…”

Direct Phosphonylation of Aromatic Azaheterocycles

“…93 However, it was not until a decade later that the lithium diisopropylamide (LDA)induced regioselective [1,3]-O,C-rearrangement of 3-and 2-pyridylphosphates into the corresponding 3-hydroxypyridin-4-yl-and 2-hydroxypyridin-3-ylphosphonates was observed and investigated. 94 On diethyl 3-pyridyl phosphate 184, readily available from 3-hydroxypyridine 183, LDA smoothly induces the [1,3]-rearrangement wherein a phosphoryl group migrates predominantly to the C-4 carbon of the heterocycle. This is likely due to the fact that orthometalation proceeds predominantly at that position.…”

“…The strong base-induced rearrangement of aryl phosphates to aryl phosphonates had already been investigated in 1981 as a useful method for the directed introduction of a phosphoryl group . However, it was not until a decade later that the lithium diisopropylamide (LDA)-induced regioselective [1,3]- O , C -rearrangement of 3- and 2-pyridylphosphates into the corresponding 3-hydroxypyridin-4-yl- and 2-hydroxypyridin-3-ylphosphonates was observed and investigated . On diethyl 3-pyridyl phosphate 184 , readily available from 3-hydroxypyridine 183 , LDA smoothly induces the [1,3]-rearrangement wherein a phosphoryl group migrates predominantly to the C-4 carbon of the heterocycle.…”