A new approach to the synthesis of 1-oxaspiro[4.n]alkanes and tetrahydrofurans by the 1,5-CH insertion reaction magnesium carbenoids

作者：Satoh Tsuyoshi^*; Yasoshima Tsukasa; Momochi Hitoshi

来源：Tetrahedron Letters, 2012, 53(16): 2074-2077.

DOI：10.1016/j.tetlet.2012.02.034

• 1-Oxaspiro[4.n]alkane
• Magnesium carbenoid
• 1,5-CH insertion reaction
• Cyclization
• CH Activation

1-Alkoxy-1-[2-chloro-2-(p-tolylsulfinyl)ethyl]cycloalkanes were prepared from various cyclic ketones in good overall yields. Treatment of these cycloalkanes bearing a sulfinyl group with i-PrMgCl resulted in the formation of 1-oxaspiro[4.n]alkanes in high to quantitative yields via the 1,5-CH insertion reaction of generated magnesium carbenoid intermediates. When this procedure was commenced with acyclic ketones, multi-substituted tetrahydrofurans were obtained in up to a 96% yield. This procedure provides a new and good way for the synthesis of 1-oxaspiro[4.n]alkanes and tetrahydrofurans with the formation of a carbon-carbon bond between a carbenoid carbon and a non-activated carbon in high yields. The oxygen atom in the magnesium carbenoid intermediates was proved to act very important roles in the 1,5-CH insertion reaction.

• 出版日期2012-4-18