Lewis Base Adducts of Phosphine-Stabilized Pb(II) Cations: Synthesis and Catalytic Hydroamination of Alkynes

Abstract

Phosphine-stabilized Pb(II) cations, generated by chloride abstraction from chloroplumbylene 1, readily react with Lewis bases (L) such as phosphines and amines to give the corresponding donor−acceptor complexes 3. These complexes 3 react with phenylacetlylene via alkyne insertion into the Pb−L bond to afford the corresponding vinylplumbylenes 4. Of particular interest, the stable complex 4-HNiPr 2 (with a secondary amine) can be used as a hydroamination catalyst of phenylacetylene.

Tetryliumylidene ions in synthesis and catalysis

“…At around the same time, the group of Kato obtained the phosphine or amine stabilised plumbyliumylidene 120, which readily reacts with phenylacetylene to the corresponding cationic vinylplumbylene 125 via alkyne insertion into the Pb–L bond ( Scheme 27 ). 125 …”

“…51 In the proposed mechanism, which was also supported by quantum chemical calculation, the Lewis acidic 119 At around the same time, the group of Kato obtained the phosphine or amine stabilised plumbyliumylidene 120, which readily reacts with phenylacetylene to the corresponding cationic vinylplumbylene 125 via alkyne insertion into the Pb-L bond (Scheme 27). 125 In the case of amine stabilisation, plumbyliumylidene 120 can catalyse the hydroamination of phenylacetylene to give the corresponding enamine 126 in a regioselective manner (Scheme 28). The yield improves drastically, when using HNEt 2 instead of HN i Pr 2 .…”

ATI Stabilized Germylene Cation as a Cyanosilylation Catalyst for Aldehydes and Ketones

“…The unique electronic nature of these compounds helps mimic the characteristics of transition metals [2] . Various low‐valent main‐group element compounds have been used as catalysts for numerous organic transformations, such as cyanosilylation, [3] hydroboration, [4] hydroamination, [4t] and hydrosilylation [5] . Among these, carbonyl compounds’ catalytic cyanosilylation produces cyanohydrins involving carbon–carbon bond formation [6] .…”