The transition‐metal‐catalyzed C−P bond cleavage has emerged as a powerful tool for the formation of both C−C and C−P bond. However, the transition‐metal‐catalyzed stereoselective cleavage of C−P bond is still undeveloped. Herein, we report a palladium‐catalyzed stereoselective cleavage of C−P bond for the construction of P‐stereogenic phosphines and stereogenic axis. This protocol enables the quick synthesis of atropisomers bearing a P‐stereogenic center in high yields, diastereo‐ and enantioselectivities of up to 98 % ee, >25 : 1 dr. The product is able to serve as chiral catalyst in phosphine catalyzed [3+2] cycloaddition of allenoates to imines, showing the great potential of the present methodology.
Chiral monodentate biaryl phosphines (MOPs) have attracted intense attention as chiral ligands over the past decades. However, the creation of structurally diverse chiral MOPs with both P- and axial chirality is still in high demand but challenging. Here, we show a distinct strategy for diversity-oriented synthesis of structurally diverse MOPs containing both P- and axial chirality enabled by enantioselective C-P bond cleavage. The key chiral PdII intermediates, generated through the stereoselective oxidative addition of C-P bond, could be trapped by alkynes, R3Si-Bpin, diboron esters or reduced by H2O/B2pin2, leading to enantioenriched structurally diverse MOPs in excellent diastereo- and enantioselectivities. Based on the outstanding properties of the parent scaffolds, the P- and axially chiral monodentate biaryl phosphines serve as excellent catalysts in asymmetric [3 + 2] annulation of MBH carbonate affording the chiral functionalized bicyclic imide.
The transition-metal-catalyzed CÀ P bond cleavage has emerged as a powerful tool for the formation of both CÀ C and CÀ P bond. However, the transition-metal-catalyzed stereoselective cleavage of CÀ P bond is still undeveloped. Herein, we report a palladium-catalyzed stereoselective cleavage of CÀ P bond for the construction of P-stereogenic phosphines and stereogenic axis. This protocol enables the quick synthesis of atropisomers bearing a P-stereogenic center in high yields, diastereo-and enantioselectivities of up to 98 % ee, > 25 : 1 dr. The product is able to serve as chiral catalyst in phosphine catalyzed [3+2] cycloaddition of allenoates to imines, showing the great potential of the present methodology.
An efficient cobalt-tertiary-amine-mediated peroxy-trifluoromethylation and halodifluoromethylation of alkenes with simple and inexpensive CF2XBr (X = F, Cl, Br) has been described. This method demonstrated broad substrate scope and good to high yields with the tolerance of mono-, di-, and trisubstituted alkenes with both electron-donating and electron-withdrawing groups. The protocol provides an efficient access to various β-peroxyl trifluoromethyl/halodifluoromethyl derivatives. Further transformation of these type of compounds to other useful molecules, such as ketene aminal, α-trifluoromethyl ketone, and gem-difluoroalkene demonstrated the utility of this methodology.
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