Synthesis of Ethers via Reaction of Carbanions and Monoperoxyacetals

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• 作者：ShivaKumar Kyasa ; Rebecca N. Meier ; Ruth A. Pardini ; Tristan K. Truttmann ; Keith T. Kuwata ; Patrick H. Dussault
• 刊名：Journal of Organic Chemistry
• 出版年：2015
• 出版时间：December 18, 2015
• 年：2015
• 卷：80
• 期：24
• 页码：12100-12114
• 全文大小：797K
• ISSN：1520-6904

文摘

Although transfer of electrophilic alkoxyl (鈥淩O+鈥? from organic peroxides to organometallics offers a complement to traditional methods for etherification, application has been limited by constraints associated with peroxide reactivity and stability. We now demonstrate that readily prepared tetrahydropyranyl monoperoxyacetals react with sp³ and sp² organolithium and organomagnesium reagents to furnish moderate to high yields of ethers. The method is successfully applied to the synthesis of alkyl, alkenyl, aryl, heteroaryl, and cyclopropyl ethers, mixed O,O-acetals, and S,S,O-orthoesters. In contrast to reactions of dialkyl and alkyl/silyl peroxides, the displacements of monoperoxyacetals provide no evidence for alkoxy radical intermediates. At the same time, the high yields observed for transfer of primary, secondary, or tertiary alkoxides, the latter involving attack on neopentyl oxygen, are inconsistent with an S_N2 mechanism. Theoretical studies suggest a mechanism involving Lewis acid promoted insertion of organometallics into the O鈥揙 bond.