Synthesis of Allenes Bearing Phosphine Oxide Groups and Investigation of Their Reactivity toward Gold Complexes

Abstract

International audienceA collection of phosphine oxide allenes has been prepared. Their coordination to gold(I) has been studied giving new coordination complexes when a pendant pyridine moiety was present. Alternatively, their gold(I)-catalyzed cycloisomerization has proven to be quite efficient. An almost complete axial-to-central chirality transfer in the cyclization process was observed, opening the potential access to valuable enantiopure phosphorus derivatives

Synthesis and structures of gold and copper carbene intermediates in catalytic amination of alkynes

“…The gold carbene signal of a related PPh 3 -ligated gold carbene 15a in the 13 C{ 1 H} NMR spectrum appears at δ =203.9 p.p.m. 63 , which is similar to that for 8 .…”

“…It should be noted that, in contrast to π-acidic phosphine ligand, the π-donating chloride ligand could increase gold-to-carbon π bonding, resulting in a short Au–C bond47. The gold carbene signal of a related PPh 3 -ligated gold carbene 15a in the 13 C{ 1 H} NMR spectrum appears at δ =203.9 p.p.m 63,. which is similar to that for 8 .…”

“…7 ). Very recently, Mouries-Mansuy, Fensterbank and colleagues 63 isolated and structurally characterized a related gold carbene 15 in the gold-mediated cyclization of pyridyl-allene.…”

“…Similar bonding scenario was also observed for the related gold complexes 15 (ref. 63 ) and 14 (ref. 62 ).…”

“…( b ) Comparison of related bond lengths and characteristic NMR spectroscopic data of complex 8 with those of reference complexes 15 and 15a ; see ref. 63. ( c ) Comparison of Mayer bond order of complex 8 with those of reference complexes 14 and 15 ; see refs 63 and 62 .…”