Efficient Ni-catalyzed asymmetric hydrogenation of cyclic N-sulfonyl ketimino esters and ketimines was successfully developed to prepare a series of chiral α-monosubstituted α-amino acid derivatives and amine derivatives with excellent results.
The iridium‐catalyzed cycloisomerization of various alkynoic acids was successfully developed, and a series of five‐, six‐, and especially seven‐membered unsaturated lactones were constructed with moderate yields and excellent regioselectivities (up to 68% yield, >99:1 rr). In addition, the indole compound can be easily prepared with 75% yield through this efficient synthetic methodology. Moreover, a plausible mechanism for this Ir‐catalyzed cycloisomerization of alkynoic acids was proposed.
The highly efficient Ni-catalyzed asymmetric hydrogenation of β-boronic ester substituted-α,β-unsaturated carboxylic esters was successfully developed using (S,S)-Ph-BPE as the ligand. A series of chiral β-borylated carboxylic esters were obtained with high yields (94%−99% yields) and excellent enantioselectivities (89%− 99% ee). The gram-scale asymmetric hydrogenation with a low catalyst loading (0.25 mol %) and synthetic transformation of hydrogenation product demonstrated the great synthetic utility of this methodology.
Chiral benzoxazinones and 4H-3,1-benzoxazines
as important motifs are widely found in abundant pharmaceuticals and
biological molecules. We herein successfully developed the first kinetic
resolution (KR) process of racemic benzoxazinones through Ir-catalyzed
asymmetric intramolecular allylation, furnishing a wide range of chiral
benzoxazinones and 4H-3,1-benzoxazines with excellent
results via outstanding KR performances (with the s factor up to 170). This protocol exhibited broad substrate scope
generality and good functional group tolerance, and the chiral 4H-3,1-benzoxazine products could be readily transformed
to other useful optically active heterocycles.
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