( R)-Goniothalamin: total syntheses and cytotoxic activity against cancer cell lines

The total syntheses of ( R)-goniothalamin ( 1) via catalytic asymmetric allylation of α-benzyloxyacetaldehyde ( 2), followed by ring-closing metathesis and Wittig olefination and via catalytic asymmetric allylation of trans-cinnamaldehyde followed by ring-closing metathesis are reported. The antiproliferative activities of ( R)- 1 and its Z-isomer 10 as well as of the synthetic dihydropyranone intermediates 7 and 8 against eight different cancer cell lines are also described. The total syntheses of ( R)-goniothalamin ( 1), a styryl lactone isolated from several Goniothalamus species, via catalytic asymmetric allylation of α-benzyloxyacetaldehyde ( 2), followed by ring-closing metathesis and Wittig olefination and via catalytic asymmetric allylation of trans-cinnamaldehyde ( 12), followed by ring-closing metathesis are reported. The antiproliferative activities of ( R)- 1 and its Z-isomer 10 as well as of the synthetic dihydropyranone intermediates 7 and 8 against eight different cancer cell lines are also described.