First Total Synthesis and Determination of the Absolute Configuration of the Stress Factor (+)-Hydroxymyoporone

Tietze, Lutz F.; Wegner, Christoph; Wulff, Christian

doi:10.1002/(sici)1521-3765(19991001)5:10<2885::aid-chem2885>3.0.co;2-8

Cited by 12 publications

(5 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…MCARs may be employed for a variety of goals in organic synthesis. Foremost, they can be used to synthesize complex structures with secondary or tertiary ethers, including oxygen-containing heterocycles, which are accessible via an intramolecular variant of the MCAR . Protected homoallylic alcohols can be formed in one step from the corresponding carbonyl compound when silyl ethers such as TMSOBn are used directly …”

Section: Applications Of the Mcar In Organic Synthesismentioning

confidence: 99%

“…Natural products with stereogenic centers bearing a tertiary methyl carbinol can easily be synthesized employing the aforementioned procedure. Thus, we were able to prepare compounds as divergent as precursors for vitamin E ( 58 ), (+)-hydroxymyoporone ( 59 ), 5,6-dihydrocineromycin B ( 60 ), and the polyoxygenated cembrene 61 by using the NPED auxiliary 38 or its derivative 53 (Scheme ).…”

Section: Nped and Derivatives Have Been Used In Total Synthesis Of Na...mentioning

confidence: 99%

See 1 more Smart Citation

The Domino Multicomponent Allylation Reaction for the Stereoselective Synthesis of Homoallylic Alcohols

2009

Self Cite

View full text Add to dashboard Cite

Stereoselective allylations of carbonyl compounds such as aldehydes and ketones are useful but challenging reactions in organic chemistry. The resulting chiral secondary and tertiary homoallylic alcohols or ethers are valuable building blocks in the synthesis of biologically active natural compounds and pharmaceuticals. Although researchers have developed several methods for the facially selective allylation of aldehydes, the stereoselective allylation of ketones still poses a severe problem. We have developed a highly diastereoselective domino multicomponent allylation reaction of a ketone and allyltrimethyl silane using the trimethylsilyl ether of a norpseudoephedrine or mandelic acid derivative as an auxiliary with a diastereoselectivity of up to 98:2. The reaction is performed at -78 degrees C in the presence of a catalytic amount of trifluoromethanesulfonic acid and leads to the corresponding tertiary ethers. The procedure can also be used for the allylation of aliphatic aldehydes with a diastereomeric ratio >99:1. Ketones give the 4,1'-syn product while the aldehydes give the reversed selectivity to yield a 4,1'-anti product. In addition, the reaction of gamma-substituted allyl silanes with ketones yields a product with two stereogenic centers and an anti diastereoselectivity of >99:1. The homoallylic ethers formed in the domino multicomponent process can be used in further synthetic transformations: the auxiliary can serve as a protecting group or can be cleaved reductively to give the corresponding homoallylic alcohols. Based on a number of both experimental and theoretical studies of the reaction mechanism, we conclude that an intermediate oxocarbenium ion is formed in the reaction of ketones. The oxocarbenium ion is attacked by the allyl silane during the stereogenic step. Using density functional theory methods, we could trace the observed stereoselectivity phenomena back to open transition states (TSs) where there is no interaction between the silane's trimethylsilyl group and the former carbonyl oxygen. On the contrary, the reaction with aldehydes forms an intermediate oxazolidinium salt, which explains the opposite selectivity. We have used the new allylation procedure in several total syntheses of natural products such as vitamin E, (+)-hydroxymyoporone, 5,6-dihydrocineromycin B, and polyoxygenated cembrenes.

show abstract

Section: Applications Of the Mcar In Organic Synthesismentioning

confidence: 99%

Section: Nped and Derivatives Have Been Used In Total Synthesis Of Na...mentioning

confidence: 99%

The Domino Multicomponent Allylation Reaction for the Stereoselective Synthesis of Homoallylic Alcohols

2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…19 The first total synthesis of the stress factor (+)-hydroxymyoporone 9 has been established and its absolute configuration reassigned. 20 The furanoterpene isodehydrodendrolasin 10 has been obtained from a tropical marine sponge Euryspongia deliculata, collected at Heron Island on the Great Barrier Reef, Australia. 21 Two homofarnesane lactones, 11 and 12, and farnesane lactone 13 have been found in the aerial parts of Gochnatia glutinosa.…”

Section: Monofuranosesquiterpenoidsmentioning

confidence: 99%

Heterocyclic terpenes: linear furano- and pyrroloterpenoids

2006

View full text Add to dashboard Cite

show abstract

“…Durch nachfolgende Reduktion der Benzylether 132 können die freien tertiären Alkohole erhalten werden, daher bietet dieses Verfahren einen indirekten Weg zu ihrer Synthese 204. Diese Strategie aus einer diastereoselektiven Sakurai‐MRC mit Ketonen und nachfolgender Reduktion von 132 wurde als stereochemischer Schlüsselschritt bei Synthesen von Naturstoffen wie der Chromaneinheit von Vitamin E,205 dem Sesquiterpen Hydroxymyoporon206 und dem Makrolid‐Antibiotikum 5,6‐Dihydrocineromycin B verwendet 207…”

Section: Asymmetrische Sakurai‐mehrkomponentenallylierungunclassified

Neue Entwicklungen in der asymmetrischen Mehrkomponenten‐Reaktion

2005

View full text Add to dashboard Cite

Unter der asymmetrischen Mehrkomponenten‐Reaktion versteht man die Synthese von chiralen Verbindungen aus drei oder mehr gleichzeitig zusammengegebenen Reaktionspartnern. Diese Art der Zugabe und Umsetzung hat gegenüber klassischen divergenten Strategien eine Reihe von Vorteilen, darunter ein geringerer Aufwand an Kosten, Zeit und Energie sowie eine bessere Umweltverträglichkeit. Dies und die hohe Stereoselektivität mancher Reaktionen werden diese neue Synthesestrategie für die chemische Industrie und für Hochschulen zunehmend wichtig machen. In diesem Aufsatz werden die Vorzüge, aber auch die Probleme asymmetrischer Mehrkomponenten‐Reaktionen diskutiert.

show abstract

First Total Synthesis and Determination of the Absolute Configuration of the Stress Factor (+)-Hydroxymyoporone

Cited by 12 publications

References 13 publications

The Domino Multicomponent Allylation Reaction for the Stereoselective Synthesis of Homoallylic Alcohols

The Domino Multicomponent Allylation Reaction for the Stereoselective Synthesis of Homoallylic Alcohols

Heterocyclic terpenes: linear furano- and pyrroloterpenoids

Neue Entwicklungen in der asymmetrischen Mehrkomponenten‐Reaktion

Contact Info

Product

Resources

About