87280-47-5Relevant articles and documents
Acyclic Stereoselection. 17. Simple Diastereoselection in the Addition of Medium- and Long-Chain n-Alkyl Ketone Lithium Enolates to Aldehydes
Heathcock, , Clayton H.,Lampe, John
, p. 4330 - 4337 (1983)
The n-alkyl tert-butyl ketones 1b-d have been prepared and the stereochemistry of their aldol reaction with benzaldehyde has been investigated.As with ketone 1a, ketones 1b-d give Z-enolates that react with benzaldehyde in THF at -78 deg C to give syn aldols.When the aldol additions are carried out in pentane, the syn aldols are also the kinetic products, but syn-anti equilibration is much more rapid in this solvent; after reaction at 25 deg C for 20 min, ketones 1c and 1d give only the anti aldols 3c and 3d.Aldolate syn-anti equilibration becomes more facile as the size of the α-alkyl group increases.Ketone 14 has been prepared and employed in a synthesis of methyl (+/-)-isocorynomycolate; the crucial aldol addition, leading to β-hydroxyketones 15 and 16, proceeds with kinetic stereoselection of only 4.5:1.
