20099-28-9Relevant articles and documents
Synthesis of 4-aryl-1,7-dihydroxyalkane-2,6-diones under aldol reaction conditions
Mavrov
, p. 714 - 720 (2016/12/27)
Reactions of 3-hydroxyalkan-2-ones with (hetero)aromatic aldehydes under basic conditions lead to 4-aryl-1,7-dihydroxyalkane-2,6-diones. These products were also synthesized by dismutation of 4-aryl-1-hydroxyalk-3-ene-2-ones. The reactions proceed as tand
(1R)-(+)-camphor and acetone derived α′-hydroxy enones in asymmetric diels-alder reaction: Catalytic activation by Lewis and bronsted acids, substrate scope, applications in syntheses, and mechanistic studies
Banuelos, Patrcia,Garcia, Jesus M.,Gomez-Bengpa, Enrique,Herrero, Ada,Odriozola, Jose M.,Oiarbide, Mikel,Palomo, Claudio,Razkin, Jesus
supporting information; experimental part, p. 1458 - 1473 (2010/06/11)
Chemical Equation Presented The Diels-Alder reaction constitutes one of the most powerful and convergent C-C bond-forming transformations and continues to be the privileged route to access cyclohexene substructures, which are widespread within natural products and bioactive constituents. Over the recent years, asymmetric catalytic Diels-Alder methodologies have experienced a tremendous advance, but still inherently difficult diene-dienophile combinations prevail, such as those involving dienes less reactive than cyclopentadiene or dienophiles like β-substituted acrylates and equivalents. Here the main features of a'-hydroxy enones as reaction partners of the Diels-Alder reaction are shown, with especial focus on their potentials and limitations in solving the above difficult cases. α'-Hydroxy enones are able to bind reversibly to both Lewis acids and Bronsted acids, forming 1,4-coordinated species that are shown to efficiently engage in these inherently difficult Diels-Alder reactions. On these bases, a convenient control of the reaction stereocontrol can be achieved using a camphor-derived chiral α'-hydroxy enone model (substrate-controlled asymmetric induction) and either Lewis acid or Bronsted acid catalysis. Complementing this approach, highly enantio- and diastereoselective Diels-Alder reactions can also be carried out by using simple achiral α'-hydroxy enones in combination with Evans' chiral Cu(II)BOX complexes (catalyst-controlled asymmetric induction). Of importance, α'-hydroxy enones showed improved reactivity profiles and levels of stereoselectivity (endo/exo and facial selectivity) as compared with other prototypical dienophiles in the reactions involving dienes less reactive than cyclopentadiene. A rationale of some of these results is provided based on both kinetic experiments and quantum calculations. Thus, kinetic measurements of Bronsted acid promoted Diels-Alder reactions of α'-hydroxy enones show a first-order rate with respect to both enone and Bronsted acid promoter. Quantum calculations also support this trend and provide a rational explanation of the observed stereochemical outcome of the reactions. Finally, these fundamental studies are complemented with applications in natural products synthesis. More specifically, a nonracemic synthesis of (-)-nicolaioidesin C is described wherein a Brαnsted acid catalyzed Diels-Alder reaction involving a α'-hydroxy enone substrate is the key step toward the hitherto challenging tri substituted cyclohexene subunit.
Novel Type of the Favorskii Rearrangement Combined with Aldol Reaction Leading to γ-Butyrolactone Derivatives
Sakai, Takashi,Yamawaki, Akitoshi,Katayama, Tsuyoshi,Okada, Hiroshi,Utaka, Masanori,Takeda, Akira
, p. 1067 - 1070 (2007/10/02)
Reaction of aromatic aldehydes or hetero-aromatic aldehydes with 3-chloro-3-methyl-2-butanone in ethanolic KOH at room temperature gave 3,3-dimethyl-5-aryltetrahydro-2-furanone as a major product.The reaction can be tentatively explained by the combination of Favorskii rearrangement and aldol reaction.
