Communic acids: occurrence, properties and use as chirons for the synthesis of bioactive compounds

Abstract

Communic acids are diterpenes with labdane skeletons found in many plant species, mainly conifers, predominating in the genus Juniperus (fam. Cupresaceae). In this review we briefly describe their distribution and different biological activities (anti- bacterial, antitumoral, hypolipidemic, relaxing smooth muscle, etc.). This paper also includes a detailed explanation of their use as chiral building blocks for the synthesis of bioactive natural products. Among other uses, communic acids have proven useful as chirons for the synthesis of quassinoids (formal), abietane antioxidants, ambrox and other perfume fixatives, podolactone herbicides, etc., featuring shorter and more efficient processes.

Figure 1

Structure of the communic acids.

Figure 2

Structures of the products obtained by epoxidation and singlet oxygen oxidation of 1a–3a.

Scheme 1

OM-OD reaction for compound 1a. OD reaction with NaBH₄.

Scheme 2

Mechanism of formation of compounds 20, 21.

Scheme 3

OM-OD reaction for compound 1a. OD reaction with Na(Hg).

Scheme 4

Ozonolysis of 1a–2a.

Scheme 5

Oxidation of 1a–2a with OsO₄/NaIO₄.

Scheme 6

Compounds synthesized from communic acids 1–3.

Scheme 7

Synthesis of ambrox 30.

Scheme 8

Synthesis of ambrox.

Scheme 9

Synthesis of ambrox.

Scheme 10

Synthesis of ambracetal.

Scheme 11

Synthesis of the tetracyclic intermediate 45.

Scheme 12

Synthesis of the intermediate 51 (precursor of bruceantin 52).

Scheme 13

Synthesis of nagilactone F, LL-Z1271γ and LL-Z1271α.

Scheme 14

Synthesis of nagilactone F, LL-Z1271γ and LL-Z1271α.

Scheme 15

Synthesis of oidiolactone C and LL-Z1271α.

Scheme 16

Synthesis of 19-hydroxyferruginol (76).

Scheme 17

Synthesis of sugikurojin (80).