Use of allyl, 2-tetrahydrofuryl, and 2-tetrahydropyranyl ethers as useful C3-, C4-, and C5-carbon sources: palladium-catalyzed allylation of aldehydes.
Palladium-diethylzinc or palladium-triethylborane catalytically promotes self-allylation of 2-(allyloxy)tetrahydrofurans, 2-(allyloxy)tetrahydropyrans, and their hydroxy derivatives on the rings (ribose, glucose, mannose, deoxyribose, deoxyglucose). All the reactions proceed at room temperature and provide polyhydroxyl products, sharing a structural motif of a homoallyl alcohol, in good to excellent yields with high levels of stereoselectivity. Useful C3-unit elongation, which makes the best use of an allyl ether as a protecting group and a nucleophilic allylation agent, is demonstrated. Mechanisms for the umpolung reaction (of an allyl ether into an allylic anion) and stereoselectivity associated with allylation of aldehydes are discussed.
Shimizu
Masamichi
M
Graduate School of Science and Technology, Nagasaki University, 1-14 Bunkyo, Nagasaki 852-8521, Japan.
Kimura
Masanari
M
Tamaru
Yoshinao
Y
D000447:Aldehydes / Q000138:chemical synthesis*; D000478:Alkylation; D000498:Allyl Compounds / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D004952:Esters / Q000737:chemistry*; D005663:Furans / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D011714:Pyrans / Q000737:chemistry*; D013237:Stereoisomerism; D015032:Zinc / Q000737:chemistry
D000447:Aldehydes; D000498:Allyl Compounds; D004952:Esters; D005663:Furans; D009942:Organometallic Compounds; D011714:Pyrans; D010165:Palladium; D015032:Zinc