New synthesis of multi-substituted alpha-chlorocyclobutanones from 1-chloro-3-cyanoalkyl p-tolyl sulfoxides by 4-Exo-Dig nucleophilic ring closure of magnesium carbenoids to nitrile group as the key reaction

作者：Saitoh Hideki; Sampei Taro; Kimura Tsutomu; Kato Yuichi; Ishida Naoyuki; Satoh Tsuyoshi^*

来源：Tetrahedron Letters, 2012, 53(24): 3004-3008.

DOI：10.1016/j.tetlet.2012.03.127

• Cyclobutanone
• alpha-Chlorocyclobutanone
• Magnesium carbenoid
• 4-Exo-Dig ring closure
• Cyclization

1-Chloro-3-cyanoalkyl p-tolyl sulfoxides were easily prepared from 1-chlorovinyl p-tolyl sulfoxides, which were synthesized from carbonyl compounds and chloromethyl p-tolyl sulfoxide, with lithium alpha-cyano carbanion of acetonitrile derivatives in good yields. Treatment of these sulfoxides with i-PrMgCl resulted in the formation of multi-substituted alpha-chlorocyclobutanones in good to high yields via the 4-Exo-Dig nucleophilic ring closure of the generated magnesium carbenoid intermediates to the nitrile group. This procedure provides a new and good way for the synthesis of multi-substituted alpha-chlorocyclobutanones from carbonyl compounds and substituted acetonitriles with formation of three carbon-carbon bonds in relatively short steps.

• 出版日期2012-6-13