A new approach to the synthesis of 1-oxaspiro[4.n]alkanes and tetrahydrofurans by the 1,5-CH insertion reaction of magnesium carbenoids
- 作者：Tsuyoshi Satoh ; tsatoh@rs.kagu.tus.ac.jp ; Tsukasa Yasoshima ; Hitoshi Momochi
- 关键词：1-Oxaspiro[4.n]alkane ; Magnesium carbenoid ; 1 ; 5-CH insertion reaction ; Cyclization ; CH Activation
- 刊名：Tetrahedron Letters
- 出版年：2012
- 期刊代码：109_00404039
- 类别：ch
- 出版时间：18 April, 2012
- 卷：53
- 期：16
- 页码：2074-2077
- 文件大小：320 K
摘要
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.