Use of Allyl, 2-Tetrahydrofuryl, and 2-Tetrahydropyranyl Ethers as Useful C3-, C4-, and C5-Carbon Sources: Palladium-Catalyzed Allylation of Aldehydes

✍ Scribed by Masamichi Shimizu; Masanari Kimura; Yoshinao Tamaru

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 274 KB
• Volume: 11
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200500450

✦ Synopsis

Abstract

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 C~3~‐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.