Total Synthesis of (−)‐Colombiasin A and (−)‐Elisapterosin B

Harrowven, David C.; Pascoe, David D.; Demurtas, Daniela; Bourne, Heather O.

doi:10.1002/anie.200462268

Cited by 108 publications

(32 citation statements)

References 31 publications

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“…24a,38,48 The allyl alcohol 38 (Scheme 11), which was prepared as an intermediate for nor- elisabethadione, appeared to be an attractive precursor for this compound. We have explored the chemistry of this intermediate in an attempt to synthesize the core skeleton of elisabethin A via a spiroannulation shown in Scheme 19.…”

Section: Resultsmentioning

confidence: 99%

Broadly Applicable Stereoselective Syntheses of Serrulatane, Amphilectane Diterpenes, and Their Diastereoisomeric Congeners Using Asymmetric Hydrovinylation for Absolute Stereochemical Control

et al. 2018

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A stereogenic center, placed at an exocyclic location next to a chiral carbon in a ring to which it is attached, is a ubiquitous structural motif seen in many bioactive natural products including di- and tri-terpenes and steroids. Installation of these centers has been a long-standing problem in organic chemistry. Few classes of compounds illustrate this problem better than serrulatanes and amphilectanes, which carry multiple methyl-bearing exocyclic chiral centers. Nickel-catalyzed asymmetric hydrovinylation (HV) of vinylarenes and 1,3-dienes such as 1-vinylcycloalkenes provide an exceptionally facile way of introducing these chiral centers. This manuscript documents our efforts to demonstrate the generality of the asymmetric HV to access not only the natural products, but also their various diastereoisomeric derivatives. Key to success here is the availability of highly tunable phosphoramidite Ni(II)-complexes useful for overcoming the inherent selectivity of the chiral intermediates. The yields for HV reactions are excellent, and selectivities are in the range of 92–99% for the desired isomers. Discovery of novel, configurationally fluxional, yet sterically less demanding, 2,2′-biphenol-derived phosphoramidite Ni-complexes (fully characterized by X-ray) turned out to be critical for success in several HV reactions. We also report, a less spectacular, yet equally important role of solvents in a metal-ammonia reduction for the installation of a key benzylic chiral center. Starting with simple oxygenated styrene derivatives we iteratively install the various exocyclic chiral centers present in typical serrulatane [e.g., a (+)-p-benzoquinone natural product, elisabethadione, nor-elisabethadione, helioporin D, a known advanced intermediate for the synthesis of colombiasin and elisapterosin] and amphilectane [e.g., A–F, G–J and K,L- pseudopterosins] derivatives. Our attempts to synthesize a hither-to elusive target, elisabethin A, led to a stereoselective, biomimetic route to pseudopterosin A–F aglycone.

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Section: Resultsmentioning

confidence: 99%

Broadly Applicable Stereoselective Syntheses of Serrulatane, Amphilectane Diterpenes, and Their Diastereoisomeric Congeners Using Asymmetric Hydrovinylation for Absolute Stereochemical Control

et al. 2018

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“…104 Dienylketene 146, formed from the cyclobutenone by microwave-assisted heating in THF, undergoes an electrocyclization, and subsequent oxidation by air affords a quinone that is used in the synthesis of the polycyclic diterpenes. A related electrocyclization of a protected hydroxy dienylketene is used in a synthesis of the antiparasitic monoterpene espintanol (Scheme 162).…”

Section: Electrocyclizations Of Vinylketenes With Alkenes and Alkynesmentioning

confidence: 99%

“…104 Subsequent air oxidation affords a quinone that is used in the synthesis of the diterpenes (−)-colombiasin A and (−)-elisapterosin B. …”

Section: Scheme 68mentioning

confidence: 99%

Cycloaddition and Electrocyclic Reactions of Vinylketenes, Allenylketenes, and Alkynylketenes

Tidwell

2015

Organic Reactions

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Vinylketenes may be prepared by the typical procedures used for other ketenes, and are usually highly reactive, except when bulky groups and silyl substituents are present. They are extensively utilized in cycloaddition reactions and electrocyclizations, including dimerizations, inter‐ and intramolecular reactions with alkenes, alkynes, imines, and carbonyl groups, and intramolecular reactions with aryl and heteroaryl groups. These pericyclic reactions are widely used in syntheses of carbocyclic and heterocyclic products, and are particularly useful for the preparation of β‐lactams and β‐lactones. Allenylketenes and alkynylketenes also undergo cycloaddition and electrocyclic reactions.

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“…[21] In addition, BT sulfones have been used in the preparation of a wide variety of olefin moieties such as dienes, [22] trienes, [22b,22c] fluoroalkenes, [23] vinyl ethers, [24] exomethylene sugars, [25] and α,β-unsaturated esters. [26] Other heterocyclic derivatives, such as pyridin-2-yl (PYR, 2), [22a,27] 1-phenyl-1H-tetrazol-5-yl (PT, 3), [28] and 1-tert-butyl-1H-tetrazol-5-yl (TBT, 4), [29] and most notably the benzothiazol-2-yl [30] and 1-phenyl-1H-tetrazol-5-yl [31] derivatives have also provided useful levels of stereoselectivity in the one-pot Julia olefination.…”

Section: Introductionmentioning

confidence: 99%

“…[11a] the versatility of these derivatives has been fully demonstrated through their application in the total synthesis of a large number of biologically active natural products [11c] such as rapamycin, [13] (+)-herboxidiene A, [14] (-)- [15] and (+)-lasonolide A, [16] rhizoxin D, [17] phorboxazole A [18] and B, [19] peridin, [20] (-)-colombiasin A, [21] and (-)-elisapterosin B. [21] In addition, BT sulfones have been used in the preparation of a wide variety of olefin moieties such as dienes, [22] trienes, [22b,22c] fluoroalkenes, [23] vinyl ethers, [24] exomethylene sugars, [25] and α,β-unsaturated esters.…”

Section: Introductionmentioning

confidence: 99%

3,5‐Bis(trifluoromethyl)phenyl Sulfones in the Julia–Kocienski Olefination – Application to the Synthesis of Tri‐ and Tetrasubstituted Olefins

2006

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3,5-Bis(trifluoromethyl)phenyl (BTFP) sulfones 8a-d are successfully employed in the modified Julia olefination reaction with carbonyl compounds employing phosphazene base P4-tBu at room temp. in THF, affording tri-and tetrasubstituted olefins in good yields. The Julia-Kocienski olefination between primary alkyl BTFP sulfones 8a,b and aromatic and aliphatic ketones affords the corresponding trisubstituted alkenes in good yields and low stereoselectivities. On the other hand, higher yields and stereoselectivities are obtained in

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Total Synthesis of (−)‐Colombiasin A and (−)‐Elisapterosin B

Abstract: Intramolecular cycloaddition reactions are central in the total syntheses of colombiasin A (1) and elisapterosin B (2) described, which use (−)‐dihydrocarvone as the starting material. A Moore rearrangement of a vinylcyclobutene is used to initiate the cycloaddition.

Cited by 108 publications

References 31 publications

Broadly Applicable Stereoselective Syntheses of Serrulatane, Amphilectane Diterpenes, and Their Diastereoisomeric Congeners Using Asymmetric Hydrovinylation for Absolute Stereochemical Control

Broadly Applicable Stereoselective Syntheses of Serrulatane, Amphilectane Diterpenes, and Their Diastereoisomeric Congeners Using Asymmetric Hydrovinylation for Absolute Stereochemical Control

Cycloaddition and Electrocyclic Reactions of Vinylketenes, Allenylketenes, and Alkynylketenes

3,5‐Bis(trifluoromethyl)phenyl Sulfones in the Julia–Kocienski Olefination – Application to the Synthesis of Tri‐ and Tetrasubstituted Olefins

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