Abstract
New chiral ferrocenylphosphines LB1–LB9 were designed and prepared through simple synthetic approaches. These air-stable ferrocenylphosphines were applied to promote asymmetric [3+2]-cycloaddition of Morita–Baylis–Hillman carbonates with maleimides, among which LB7 was shown to have good catalytic activity to afford the corresponding multifunctional cyclopentenes in up to 59% yield and up to 53% ee under mild reaction conditions. A plausible reaction mechanism was proposed.
GRAPHICAL ABSTRACT
Notes
a Unless otherwise specified, the reactions were performed with 1a (0.5 mmol) and 2a (1 mmol) and catalyst (0.05 mmol) in toluene (1.0 mL) at room temperature.
b Isolated yield.
c The ee value was determined by HPLC analysis using a chiral column.
a Unless otherwise specified, the reactions were performed with 1a (0.5 mmol), 2a (1 mmol), and LB7 (0.05 mmol) in toluene (1.0 mL) at room temperature.
b Isolated yield.
c The ee value was determined by HPLC analysis using a chiral column.
a Unless otherwise specified, the reactions were performed with 1a (0.5 mmol), 2a (1 mmol), and LB7 (0.05 mmol) in toluene (1.0 mL) at room temperature.
b Isolated yield.
c The ee value was determined by HPLC analysis using a chiral column.
d The reaction temperature is 40 °C.
e The ee value was not detected.