3 research outputs found
Directed <i>Ortho</i>-Lithiation of Aminophosphazenes: An Efficient Route to the Stereoselective Synthesis of <i>P</i>āChiral Compounds
<i>Ortho</i>-directed lithiation of <i>P</i>,<i>P</i>-diphenylaminophosphazenes followed by electrophilic quench is described as an efficient process for synthesizing <i>P</i>-chiral <i>ortho</i>-functionalized derivatives in high yields and diastereoselectivities. The method allows the tunable preparation of structurally diverse enantiopure <i>P</i>-chiral compounds including phosphinic and phosphinothioic amides, phosphinic esters, phosphine oxides, and <i>o</i>-aminophosphines
Phyllanthus emblica
The experimentally observed stereomutation of spiro-1,2-oxaphosphetanes
is shown by DFT calculations to proceed through successive M<sub>B2</sub> or M<sub>B4</sub> and M<sub>B3</sub> mechanisms involving two, four,
and three Berry pseudorotations at phosphorus, respectively. Oxaphosphetane
decomposition takes place in a single step via a polar transition
state. The calculated activation parameters for this reaction are
in good agreement with those determined experimentally
Cycloaurated Phosphinothioic Amide Complex as a Precursor of Gold(I) Nanoparticles: Efficient Catalysts for A<sup>3</sup> Synthesis of Propargylamines under Solvent-Free Conditions
A C,S-cycloaurated complex based
on an ortho-substituted phosphinothioic
amide framework has been synthesized in high yield through tinĀ(IV)āAuĀ(III)
transmetalation from the corresponding chlorodimethylstannyl derivative.
The latter was prepared in a two-step process involving directed ortho
lithiation/quenching with Me<sub>3</sub>SnCl followed by Me/Cl exchange.
The tinĀ(IV) and goldĀ(III) complexes have been characterized in solution
and in the solid state. In both complexes, the phosphinothioic amide
moiety acts as a CāCāPāS pincer ligand with formation
of five-membered-ring metalacycles. The use of the goldĀ(III) complex
in the amineāaldehydeāalkyne (A<sup>3</sup>) three-component
coupling synthesis of propargylamines showed that the compound is
transformed into the Sonogashira-type <i>o</i>-alkynylphosphinothioic
amide with generation of AuĀ(I) nanoparticles with an average size
of around 7 nm. These nanoparticles proved to be excellent catalysts
in A<sup>3</sup> coupling processes, providing propargylamines in
high yields under solvent-free conditions with loadings as low as
0.1 mol % and without the use of additives