[36700-07-9] · C36H84NiO12P4 · Tetrakis(triisopropyl phosphite)nickel(0) · (MW 891.77)
Physical Data: mp 187 °C.
Preparative Methods: most conveniently synthesized by the reaction of Bis(1,5-cyclooctadiene)nickel(0) with Triisopropyl Phosphite.6
Handling, Storage, and Precautions: is a cancer suspect agent; air sensitive; should be handled using Schlenk or glove box techniques. Use in a fume hood.
[(i-PrO)3P]4Ni efficiently catalyzes the allylation of alkynes and phenylhydrazones with allyl esters. The reaction of phenylhydrazones with allyl acetate using 5 mol % [(i-PrO)3P]4Ni produces azo compounds (eq 1).1 [(i-PrO)3P]4Ni was superior to Ni0 complexes of other alkyl and aryl phosphites.
Alkynes react with allyl but-3-enoate in the presence of 2 mol % [(i-PrO)3P]4Ni at room temperature to form nonconjugated eneynes in high yield (eq 2).2 [(i-PrO)3P]4Ni was determined to be the optimum catalyst for this transformation.
In the absence of alkynes, allyl but-3-enoate is rearranged by [(i-PrO)3P]4Ni to a mixture of isomeric heptadienoic acids (eq 3).3 A 2:1 ratio of isomeric carboxylic acids was formed with [(i-PrO)3P]4Ni. For comparison, Tetrakis(triethyl phosphite)nickel(0) gave a 0.8:1 mixture.
Dihydroindoles can be prepared by the dimerization of dipropargylamines with alkynes using catalytic amounts of [(i-PrO)3P]4Ni (eq 4).4 Norbornadiene derivatives can be cyclodimerized with allyl acetate in the presence of [(i-PrO)3P]4Ni to give tricyclononane products (eq 5).7
Addition of amines to vinylcyclopropanes is catalyzed by [(i-PrO)3P]4Ni to give acyclic allylic amines (eq 6).5 This reaction is also catalyzed by Tetrakis(triphenylphosphine)palladium(0) in comparable yield. The reaction of amines with vinyl lactones gave allylamino carboxylic acids.
Gregory T. Whiteker
Union Carbide Corporation, South Charleston, WV, USA