Deconjugative alkylation of the enolate anion derived from ethyl crotonate

Herrmann, J.; KIECZYKOWSKI, G. R.; Schlessinger, R. H.

doi:10.1016/s0040-4039(01)96239-2

Cited by 172 publications

(93 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(1)]. [9] In 1972, Rathke and Sullivan reported the first successful enolization of an a,b-unsaturated ester, 5, by the combination of a bulky amide base (lithium N-isopropylcyclohexylamide (LiICA)) and HMPA [Scheme 5, Eq. (2)].…”

Section: Early Developments In the Vinylogous Aldol Reactionmentioning

confidence: 99%

“…(3)]. [9] The high a-site selectivity observed in these alkylations illustrates an important feature of dienolate chemistry: The vinylogous transmission of electronic effects does not guarantee that reaction at the remote position will be favored or [1] even observed. However, high g selectivity is possible through the use of latent dienolate equivalents in Mukaiyama-type aldol reactions [2] promoted by Lewis acids.…”

Section: Early Developments In the Vinylogous Aldol Reactionmentioning

confidence: 99%

“…Successful methods for the preparation of metallodienolates derived from a,b-unsaturated esters. [9,10] HMPA = hexamethyl phosphoramide. selectivity in ketone dienol ethers may be attenuated compared to silyl ketene acetals.…”

Section: Early Developments In the Vinylogous Aldol Reactionmentioning

confidence: 99%

See 2 more Smart Citations

Catalytic, Enantioselective, Vinylogous Aldol Reactions

Denmark¹,

Heemstra²,

Beutner³

2005

Angew Chem Int Ed

444

149

View full text Add to dashboard Cite

In 1935, R. C. Fuson formulated the principle of vinylogy to explain how the influence of a functional group may be felt at a distant point in the molecule when this position is connected by conjugated double-bond linkages to the group. In polar reactions, this concept allows the extension of the electrophilic or nucleophilic character of a functional group through the pi system of a carbon-carbon double bond. This vinylogous extension has been applied to the aldol reaction by employing "extended" dienol ethers derived from gamma-enolizable alpha,beta-unsaturated carbonyl compounds. Since 1994, several methods for the catalytic, enantioselective, vinylogous aldol reaction have appeared, with which varying degrees of regio- (site), enantio-, and diastereoselectivity can be attained. In this Review, the current scope and limitations of this transformation, as well as its application in natural product synthesis, are discussed.

show abstract

Section: Early Developments In the Vinylogous Aldol Reactionmentioning

confidence: 99%

Section: Early Developments In the Vinylogous Aldol Reactionmentioning

confidence: 99%

See 1 more Smart Citation

Catalytic, Enantioselective, Vinylogous Aldol Reactions

Denmark¹,

Heemstra²,

Beutner³

2005

Angew Chem Int Ed

444

149

View full text Add to dashboard Cite

show abstract

“…In fact this reaction gave a complex mixture in which the desired product was not detected. This is presumably due to the fact that lithium diisopropylamide reacts, in the absence of HMPA, with the m,P-unsaturated ester moiety to give the Michael adduct (15). The deprotonation at the y-position of this unsaturated ester moiety also creates more complications in the reaction with LDA-HMPA.…”

Section: A 136mentioning

confidence: 99%

Nuclear analogs of β-lactam antibiotics. XV. Synthesis of 6-substituted 2-methylpenem-3-carboxylic acids

Ueda¹,

Martel²,

Daris³

et al. 1982

Can. J. Chem.

View full text Add to dashboard Cite

The synthesis of 6-substituted 2-methylpenem-3-carboxylic acids is described. The dianion 6 was prepared insitu from 2-methylpenem-3-carboxylic acid (5) by the addition of two equivalents of n-butyllithium in THF at −78 °C. This dianion reacted with deuterated acetic acid, acetone, acetaldehyde, benzaldehyde, and methyl thiomethylsulfonate to give 6-deuterio-, 6-(2′-hydroxy-2′-propyl)-, 6-(1′-hydroxyethyl)-, 6-(1′-hydroxybenzyl)-, 6-methylthio-2-methylpenem-3-carboxylic acids and their sodium or potassium salts, 7–11, respectively. The stereochemistry of the products is also discussed.

show abstract

“…[1] Im Kontext der Aldolreaktion bekommt dieses Konzept eine besondere Relevanz: Während Metalldienolate oftmals Mischungen aus a-und g-Additionsprodukten ergeben, [2] reagieren entsprechende Dienolsilane mit hoher Selektivität an der vinylogen g-Position.…”

unclassified

Disulfonimid‐katalysierte asymmetrische vinyloge und bisvinyloge Mukaiyama‐Aldolreaktionen

et al. 2010

View full text Add to dashboard Cite

Sechs auf einen Streich: Eine vinyloge Mukaiyama‐Aldoladdition von Crotonsäure‐abgeleiteten Nucleophilen an Aldehyde mit chiralem Disulfonimid als Katalysator nutzt das Konzept der Vinylogie, das auch auf doppelt vinyloge Sorbinsäurederivate als Nucleophile erweitert werden konnte – ein Beispiel für eine zuvor unbekannte, ε‐selektive bisvinyloge Mukaiyama‐Aldoladdition, die das Aldehydsubstrat direkt um sechs Kohlenstoffatome verlängert (siehe Schema).

show abstract

Deconjugative alkylation of the enolate anion derived from ethyl crotonate

Cited by 172 publications

References 1 publication

Catalytic, Enantioselective, Vinylogous Aldol Reactions

Catalytic, Enantioselective, Vinylogous Aldol Reactions

Nuclear analogs of β-lactam antibiotics. XV. Synthesis of 6-substituted 2-methylpenem-3-carboxylic acids

Disulfonimid‐katalysierte asymmetrische vinyloge und bisvinyloge Mukaiyama‐Aldolreaktionen

Contact Info

Product

Resources

About