Catalytic, enantioselective, vinylogous aldol reactions.
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.
Denmark
Scott E
SE
Roger Adams Laboratory, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA. denmark@scs.uiuc.edu
Heemstra
John R
JR
Beutner
Gregory L
GL
D000447:Aldehydes / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D004987:Ethers / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism
D000447:Aldehydes; D004987:Ethers; D007659:Ketones