A nickel-catalyzed asymmetric allylation of secondary phosphine oxides (SPO) for the synthesis of tertiary phosphine oxides (TPO) was realized with high enantioselectivity. The dynamic kinetic asymmetric transformation of SPO was accomplished in the presence of nickel complex. By elucidating the absolute configurations of the reacted SPO starting material and the TPO product, we confirmed that the allylation reaction proceeded through a P-stereo retention process. The protocol represents the first example of synthesizing Pstereogenic phosphine oxides by allylation reaction.
The practical synthesis of P-stereogenic tertiary
phosphines, which have wide applications in asymmetric catalysis,
materials, and pharmaceutical chemistry, represents a significant
challenge. A regio- and enantioselective hydrophosphination using
cheap and ubiquitous alkynes catalyzed by a nickel complex was designed,
in which the toxic and air-sensitive secondary phosphines were prepared in situ from bench-stable secondary phosphine oxides. This
methodology has been demonstrated with unprecedented substrate scope
and functional group compatibility to afford electronically and structurally
diversified P(III) compounds. The products could be easily converted
into various precursors of bidentate ligands and organocatalysts,
as well as a variety of transition-metal complexes containing both P- and metal-stereogenic centers.
The
asymmetric synthesis of P-stereogenic phosphinates
through allylic alkylation of H-phosphinates has
been developed. With H-phosphinates and allylic acetates
as the starting materials, a variety of allylic P-chiral phosphinates were accessed in high enantioselectivities of
up to 92% ee and generally high yields. In addition, a further study
demonstrated the applicability of this protocol, including the scale-up
synthesis and facile transformation of chiral products from phosphinates
to phosphine oxides with organolithium reagents under mild reaction
conditions.
P-stereogenic compounds have found wide applications in asymmetric catalysis and medicinal chemistry. Due to the high reactivity of the triple bond, P-stereogenic alkynylphosphines could be easily derivatized, serving as universal...
Activated vinylcyclopropanes (VCPs) can form zwitterionic π-allylmetal species in the presence of transition metals and are widely used in organic synthesis. A nickel-catalyzed asymmetric allylation of secondary phosphine oxide with...
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