Synthesis of the Prelog-Djerassi Lactone and Protomycinolide IV Based on the Stereospecific Methylation of γ,δ-Epoxy Acrylates by Trimethylaluminum

Miyashita, Masaaki; Hoshino, M.; Yoshikoshi, Akira; Kawamine, Katsumi; Yoshihara, Kousei; Irie, Hiroshi

doi:10.1246/cl.1992.1101

Cited by 15 publications

(7 citation statements)

References 12 publications

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“…We planned on developing and applying this tandem sequence in the context of synthesizing the Prelog–Djerassi lactone ( 4 ), which has served as a touchstone molecule for showcasing many synthetic methods for polypropionate synthesis. Over 30 different syntheses of the PD lactone ( 4 ) have been recorded, and the most recent of these are summarized in Table . − …”

Section: Resultsmentioning

confidence: 99%

Asymmetric Hydroformylation-Initiated Tandem Sequences for Syntheses of (+)-Patulolide C, (−)-Pyrenophorol, (+)-Decarestrictine L, and (+)-Prelog Djerassi Lactone

2014

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Four different Rh-catalyzed asymmetric hydroformylation (AHF) tandem reactions have been developed in the context of the total syntheses of (+)-patulolide C, (-)-pyrenophorol, (+)-decarestrictine L, and (+)-Prelog-Djerassi lactone. A total synthesis of (+)-patulolide C has been accomplished in three steps utilizing a Rh(I)-catalyzed Z-selective anti-Markovnikov hydroacetoxylation of a known alkyne to give a Z-enol acetate with excellent selectivity. An AHF/intramolecular Wittig olefination cascade was utilized to set the C4-hydroxyl stereochemistry, E-olefin geometry, and form the macrolactone. In addition, both (-)-pyrenophorol and (+)-decarestrictine L have been synthesized from the enantiomeric (4R)- and (4S)-4-(tert-butyldimethylsiloxy)-1-pentyne in five and four steps, respectively. These syntheses feature Ru(II)-catalyzed Z-selective anti-Markovnikov hydroacetoxylation of terminal alkynes followed by AHF/Wittig olefination sequences to rapidly establish functionality and stereogenicity. A synthesis of (+)-Prelog-Djerassi lactone was accomplished in three isolations from the known 1-vinyl-4-methyl-2,6,7-trioxabicyclo[2.2.2]octane ortho ester. An AHF/crotylation tandem sequence has been developed to set the C2-C4 stereochemistry. An asymmetric hydrogenation was employed to set the C6 stereochemistry, resulting in an especially efficient enantioselective synthesis from achiral starting material. In summary, these syntheses have greatly improved efficiency in terms of atom-economy, catalytic stereoselective transformations, inexpensive reagents, step-counts, and overall yield when compared with previous synthetic attempts.

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Section: Resultsmentioning

confidence: 99%

Asymmetric Hydroformylation-Initiated Tandem Sequences for Syntheses of (+)-Patulolide C, (−)-Pyrenophorol, (+)-Decarestrictine L, and (+)-Prelog Djerassi Lactone

2014

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“…It is mooted that the water probably reacts with Me 3 Al to give species such as R 2 AlOAlR 2 and R 3 AlO which are potent methylating agents. 11 It should be noted that under these conditions the reaction occurred with inversion of configuration, predominantly.…”

Section: Synthesis Of (S)-2-phenylpropanoic Acidmentioning

confidence: 90%

“…Thus chalcone was converted into the epoxide (Ϫ)-6 (95% ee) using poly-()-leucine adsorbed onto silica, 9 together with urea-hydrogen peroxide and diazabicycloundecene (DBU) in tetrahydrofuran (THF). Alkylation with epoxide ring-opening was accomplished using trimethylaluminium under conditions recommended by Miyashita et al 10,11 Thus trimethylaluminium (10 mol equiv.) was added dropwise to a stirred solution of epoxychalcone (Ϫ)-6 (1 equiv.)…”

Section: Synthesis Of (S)-2-phenylpropanoic Acidmentioning

confidence: 99%

Stereocontrolled ring-opening of some enantiomerically enriched epoxy ketones and epoxy alcohols using trimethylaluminium: synthesis of (S )-2-arylpropanoic acids

Carde

Davies

Roberts

2000

J. Chem. Soc., Perkin Trans. 1

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“…Since 1990 several syntheses have been published including one from trans -pulegenic acid, three from the Roche ester, − a racemic synthesis from cyclopentanone, a desymmetrization of a meso dialdehyde, and an Ireland–Claisen rearrangement . Clearly, the PD lactone ( 1 ) has provided a popular context to display a diverse range of methods and strategies for polypropionate natural product synthesis.…”

mentioning

confidence: 99%

Synthesis of the Prelog–Djerassi Lactone via an Asymmetric Hydroformylation/Crotylation Tandem Sequence

Risi

Burke

2012

Org. Lett.

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A synthesis of the Prelog-Djerassi lactone [(+)-1] has been accomplished in three isolations and 57% overall yield from the known vinyl ortho ester 2. A Rh(I)-catalyzed asymmetric hydroformylation/crotylation tandem sequence has been developed and used to set the C2-C4 stereochemistry. A Rh(I)-catalyzed asymmetric hydrogenation was employed to set the C6 sterechemistry, resulting in an unusually short and efficient enantioselective synthesis of this touchstone molecule from achiral starting material.

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Synthesis of the Prelog-Djerassi Lactone and Protomycinolide IV Based on the Stereospecific Methylation of γ,δ-Epoxy Acrylates by Trimethylaluminum

Cited by 15 publications

References 12 publications

Asymmetric Hydroformylation-Initiated Tandem Sequences for Syntheses of (+)-Patulolide C, (−)-Pyrenophorol, (+)-Decarestrictine L, and (+)-Prelog Djerassi Lactone

Asymmetric Hydroformylation-Initiated Tandem Sequences for Syntheses of (+)-Patulolide C, (−)-Pyrenophorol, (+)-Decarestrictine L, and (+)-Prelog Djerassi Lactone

Stereocontrolled ring-opening of some enantiomerically enriched epoxy ketones and epoxy alcohols using trimethylaluminium: synthesis of (S )-2-arylpropanoic acids

Synthesis of the Prelog–Djerassi Lactone via an Asymmetric Hydroformylation/Crotylation Tandem Sequence

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