Fig. 3: Selected optimization studies on bifunctional chiral phosphonium salts. | Nature Communications

Fig. 3: Selected optimization studies on bifunctional chiral phosphonium salts.

From: Asymmetric synthesis of N-bridged [3.3.1] ring systems by phosphonium salt/Lewis acid relay catalysis

Fig. 3

aReaction condition: substrates 1a (0.10 mmol) and 2a (0.12 mmol) in the presence of P (0.01 mmol) and Cs2CO3 (0.40 mmol) in toluene (2.0 mL) at r.t. for 36 h; then BF3·Et2O (1.0 mmol) was directly added to the reaction mixture which was further stirred at r.t. for 12 h. bOptimal conditions: the reaction was performed with 6.0 equiv. of Cs2CO3 in Et2O at −20 °C for 72 h; and then BF3.Et2O was directly added at r.t. for further stirring 12 h (see the SI for more details).

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