Direct 1,1-Bisphosphonation of Isocyanides: Atom- and Step-Economical Access to Bisphosphinoylaminomethanes

Abstract

An atom- and step-economical strategy for the synthesis of bisphosphinoylaminomethanes is reported. This metal-free bisphosphinylation reaction proceeded smoothly through a base-mediated direct 1,1-bisphosphonation of phosphine oxides and isocyanides under mild conditions. The present method offers a facile, efficient, and general approach to a broad range of bisphosphinoylaminomethane derivatives in moderate to good yields.

Metal-free direct C–H phosphonation of N-heterocycles with diphenylphosphine oxides under mild conditions

“…A plausible mechanism based on the above studies and the previous literature 41,56–61 is proposed in Scheme 5b. First, phosphite 2a′ is generated via tautomerization of phosphine oxide 2a , which is deprotonated by DBU to afford a phosphine oxide anion.…”

Copper‐Catalyzed One‐Pot Three‐Component Aminophosphinoylation of 1,4‐Naphthoquinone

“…Based on the above control experiment results and previous reports, a plausible mechanism was proposed in Scheme 4. Firstly, phosphite 2 a′ generated via tautomerization of phosphine oxide 2 a , and further deprotonation by KOH to form phosphine oxide anion [18,19] . Then perform a Michael addition reaction with 1 a to generate intermediate A .…”

“…Firstly, phosphite 2 a' generated via tautomerization of phosphine oxide 2 a, and further deprotonation by KOH to form phosphine oxide anion. [18,19] Then perform a Michael addition reaction with 1 a to generate intermediate A. Which was rapidly oxidized by oxygen to obtain phosphinoylation product 6.…”

Silver-catalyzed P-centered anion nucleophilic addition to isocyanide: access to 2-phosphinoyl indoles/indol-3-ols

“…When 3-(2-isocyanophenyl)acrylate ( 1m ), 3-(2-isocyanophenyl)acrylonitrile ( 1n ) and 1-isocyano-2-styrylbenzene ( 1o ) were used as the substrates, the bisphosphinoylaminomethanes 7a–c were obtained in high yields, and the corresponding 2-phosphinoylindole products could not be detected (Scheme 4a). These results indicate that an anionic 1,1-bisphosphonation of isocyanides with diphenylphosphine oxide 2a occurred under the standard conditions, 18 rather than a radical pathway towards 2-phosphinoylindoles. 10 Furthermore, the reactions performed in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO, 2.0 equiv.)…”