Alkylation of Acetals Using Manganate—BF3×OEt2 Mixed Reagent.

A mixture of `R3MnMgBr' and BF3·OEt2 prepared in advance only by stirring both reagents in ether converted acetals to alkylation products, where an alkoxy group of acetals was substituted by the alkyl group of manganese reagent used. Ketals also reacted with the `mixed reagent' to afford the corresponding alkylation products in high yield. α-Alkoxy-substituted cyclic ethers and acetoxy-substituted cyclic ethers were selectively converted to ring-opening alkylation products and α-alkyl-substituted cyclic ethers, respectively.