Zamoranic Acid Research Articles

Semisynthesis of (+)-angeloyl-gutierrezianolic acid methyl ester diterpenoid

This paper describes the use of zamoranic acid in the first semisynthesis of the furolabdane (+)-angeloyl-gutierrezianolic acid methyl ester diterpenoid, which also establishes the absolute configuration of the natural product. Direct deconjugation of Δ 7 in zamoranic acid and Bestmann methodology for the furan ring synthesis are the key steps.

Synthesis of tri- and tetracyclic diterpenes. Cyclisations promoted by SmI 2

Several tri- and tetracyclic diterpenes have been synthesised from zamoranic acid. The key step is the cyclisation of a dicarbonyl 13,14-secoderivative by SmI 2.

Synthesis of (+)‐Totarol.

(+)-Totarol, a tricyclic diterpene, has been synthesised from zamoranic acid. The key step is the cyclisation of a 13,14-secototarane using SmI 2 .

Synthesis of (+)-totarol

(+)-Totarol, a tricyclic diterpene, has been synthesised from zamoranic acid. The key step is the cyclisation of a 13,14-secototarane using SmI 2.

Synthesis and Absolute Configuration of (‐)‐Chrysolic Acid and (+)‐Isofregenedol.

Abstract An efficient synthesis of (−)-chrysolic acid and (+)-isofregenedol has been achieved from zamoranic acid and sclareol. The characteristic tetrahydronaphtalenic system was obtained by use of a cationic rearrangement of bicyclic systems adequately functionalized. The absolute configuration of the natural products was established using Sharpless asymmetric epoxidation.

Synthesis and absolute configuration of (−)-chrysolic acid and (+)-isofregenedol

An efficient synthesis of (−)-chrysolic acid and (+)-isofregenedol has been achieved from zamoranic acid and sclareol. The characteristic tetrahydronaphtalenic system was obtained by use of a cationic rearrangement of bicyclic systems adequately functionalized. The absolute configuration of the natural products was established using Sharpless asymmetric epoxidation.

Cyclization of Bicyclic Diterpenes Promoted by SmI2. Synthesis of Tri- and Tetracyclic Diterpenes

The synthesis of 15-hibaen-14-one (a tetracyclic diterpene) is described from zamoranic acid as starting material in an excellent yield and with total control of the stereochemistry. The key step is a SmI 2 promoted pinacol cyclization.

Synthesis of (+)-limonidilactone and 12- epi-limonidilactone

The synthesis of (+)-limonidilactone from zamoranic acid is described. This synthesis has allowed the absolute configuration for the natural product (−)-limonidilactone be established. The synthesis of 12- epi-limonidilactone is also realized. In addition, a solid compound, which possesses a carbonyl group, has been isolated and identified as a hydrate stabilized by three hydrogen bonds.

An Efficient Total Synthesis of Isodrimeninol from Zamoranic Acid

An efficient total synthesis of isodrimeninol (1) has been achieved from zamoranic acid (3) employing a regioselective Lewis acid mediated elimination-isomerisation as the key step. Following oxidative cleavage of the resulting conjugated diene to the methyl ketone, standard manipulations allowed the synthesis of allylic alcohols 10 which, after a highly diastereoselective epoxidation and subsequent lactonisation, allowed the synthesis of the natural product in 11 steps and 56% overall yield.

Synthesis of (+)-limonidilactone: Absolute configuration of (−)-limonidilactone

The synthesis of (+)-limonidilactone has been achieved from zamoranic acid in 6 steps with an overall yield of 25%. The absolute configuration of (−)-limonidilactone has been established, as a natural labdane belonging to the antipode series.

Chemistry of zamoranic acid. Part 10. Homochiral hemisynthesis of pereniporin A

The synthetic versatility of 12-acetoxydrima-7,9(11)-diene 1 obtained from 15-hydroxylabda-7,13-dien-17-oic acid (zamoranic acid), as a key intermediate in the homochiral semisynthesis of highly functionalized drimanes such as pereniporin A 3, an important antibiotic, through the carbonate 2, is highlighted.

Chemistry of zamoranic acid. Part IX homochiral synthesis of polygodial and warburganal from 17-acetoxy-7-labden-15-ol

14,15-di nor-17-acetoxy-7-labden-13-one, 4 was prepared from zamoranic acid methyl ester 5. Photochemical cleavage of 4 gave 12-acetoxy-7,9(11)-drimadiene, 3, in 75% overall yield. The chemo- and diastereoselective epoxidation of 3 afforded 12-acetoxy-9α and 9β(11)-epoxy-7-drimene, 17 and 18 in 4:1 ratio. Ring-opening of 17 (or the mixture 17 18 ) using BF 3·Et 2O or ring-opening of the mixture 17 18 lead to the synthetic precursor of polygodial: (9 R)-12-acetoxy-drimen-11-al, 20, with a 90% diastereoisomeric excess. The chemo- and diastereoselective cis-hydroxylation of diene 3 led to the synthetic precursor of warburganal 9α,11,12-trihydroxy-7-drimene, 29 with 47% yield. Polygodial and warburganal were prepared from zamoranic acid methyl ester in 55 and 27% overall yield, respectively.

Transformation of Labdanes into Drimanes. Semisyntheses of Poligodial and Warburganal from Zamoranic Acid

Abstract The photochemical rupture of methyl 14,15–dinor–13–oxo–7-labden–15–oate leads to a diene (methyl 7,9(11)–drimadien–12–oate) whose chemoselective epoxidation affords methyl 9α,11–epoxy–7–drimen–12–oate. Diastereoselective rearrangement with Lewis acids produces methyl 9R,11–oxo–7–drimen–12–oate, a precursor of poligodial and warburganal.

Diastereoselective ring—opening of 12-acetoxy-9α and 9β(11)-epoxy-7-drimene: Homochiral semisynthesis of poligodial and warburganal

Starting from a zamoranic acid derivative (Methyl 15-tetrahydropiranyloxy-7-labden-17-oate) poligodial and warburganal have been synthesized in several steps with a 55% overall yield and 27% overall yield, respectively.

Chemistry of zamoranic acid. Part V Homochiral semisyntheses of active drimanes: Pereniporin B, polygodial and warburganal

Methyl 14,15-di nor-13-oxo-7-labden-15-oate was obtained from acid zamoranic acid methyl ester. The former by photochemical cleavage yielded methyl 7,9(11)-drimadien-12-oate, whose chemoselective epoxidation afforded methyl 9α,11-epoxy-7-drimen-12-oate, which is the key synthetic precursor for pereniporin B, polygodial and warbuganal.