Yields of mixed bis-pyrrolizidino/-thiopyrrolizidino dispiro-oxindolo-acenaphthylino curcuminoids 7A–D.

Entrya	R1	R2	R3	X	Product	Yieldb (%)
1	H	H	H	–CH2	7A	54
2	H	I	H	–CH2	7B	56
3	H	H	H	–S	7C	50
4	H	Me	H	–S	7D	49

^aUnless otherwise noted, the reaction was performed with 1.76 mmol of 3A-D(a) (±), isatins and proline in 50.0 mL of MeOH under reflux for 8 h.

^bDetermined after isolation.