We have developed a series of novel BINOL-based phosphines. These bifunctional organocatalysts
can be used in the [3+2] cycloaddition of electron-deficient olefins and Morita–Baylis–Hillman
(MBH) carbonates. Moderate to excellent yields (up to >99%) and good to excellent
enantioselectivities (up to 95% ee) can be obtained in the cycloaddition reaction
of maleimides and MBH carbonates. The application of these novel phosphines can be
further extended to the asymmetric synthesis of chiral spirooxindoles (up to 85% ee).
The results in this study indicate that the BINOL moiety plays an important role in
stereocontrol.
Key words
BINOL - phosphine - organocatalyst - Morita–Baylis–Hillman derivative - cycloaddition