Abstract: Cyclopropane-containing natural products have received considerable attention as the synthetic targets due to their significant effects on bioactivities with concomitant medical and agricultural implications. We recently reported a valuable synthetic route to spiro-cyclopropane-butinolied derivatives containing multiple stereogenic centers, using 5-L-menthyloxy-3-bromo-2(5H)-furanone, and different nucleophiles by tandem double Michael addition/internal nucleophilic substitution. On the basis of the previous work, the synthesis of 4-methoxy-2-bromobutyrolactone (4) was conveniently achieved from 4-hydroxybutyrolactone (2) as a starting material through the acetalization of methanol. 2-Bromobutyrolactone (4) as a synthon reacts with various nucleophiles under mild conditions to form the diversely functionalized spiro-cyclopropane derivatives 8a—8d via tandem double Michael addition/intramolecular nucleophilic substitution. Spiro-cyclopropane compounds 8a—8d were identified on the basis of their elemental analysis and spectroscopic data, such as IR, ¹H NMR, ¹³C NMR and MS. The stereochemistry and configuration of the spiro-cyclopropane compound 8d was measured by X-ray crystallography. This result provides an efficient synthetic route to the interesting functionalized target molecules 8 with 4-methoxy-2-bromobutyrolactone (4) as a cheap substrate. It could be furnished further an important synthetic strategy for some complex cyclic natural and nonnatural products.

Key words: 4-Methoxy-2-bromobutyrolactone, Tandem reaction, Spiro-cyclopropane derivatives, (X-ray) crystallography determination