Synthesis of (+)-Malettinin C and (+)-Malettinin E

Key words

(+)-malettinin C - (+)-malettinin E - asymmetric organocatalytic aldol reaction - Buchner ring expansion - Dess–Martin oxidation - oxidative dearomatization

Significance

Yokoshima and Umekubo report the synthesis of two tropolone-containing natural products, namely (+)-malettinin C and (+)-malettinin E. These compounds possess high binding affinities to metal ions and therefore serve as inhibitors to a range of metalloenzymes.

Comment

Synthetic endeavors started with an organocatalytic asymmetric aldol reaction. PIFA-­mediated oxidative dearomatization of phenol K led to spirocycle M, which was converted to tropolone O in a base-mediated ring expansion, paving the way to malettinins C and E. Moreover, the authors showcased an improved cyclization sequence by replacing the nitro group in J by a sulfonyl group.

Publication History

Article published online:
16 August 2023