172947-03-4Relevant academic research and scientific papers
Novel Routes to Enol Ethers, Unsymmetrical Ketones, α-Bromoalkyl Ketones, 1,4-Diketones, 2-Ethoxy-2-cyclopenetenones, and α-Keto Enamines
Katritzky, Alan R.,Zhang, Guifen,Jiang, Jinlong
, p. 7605 - 7611 (2007/10/03)
Highly regioselectve SN2' reactions of adducts 6 (readily prepared by reactions of halides with the allyl anion 12 of 11) with Grignard reagents gave enol ethers 13, which were converted (in one-pot reactions from 11) into ketones 14 and α-bromoalkyl ketones 15 in good yields.The monoprotected 1,4-diketone derivative 16 (prepared by Michael addition of the allyl anion 12 with methyl vinyl ketone) was converted both into 1,4-diketones 18 and into protected γ-hydroxyalkyl ketone 20 by propenoyl, or to both functionalities.The allyl anion 12 with α-substituted acetic esters gave α-acylated adducts 24, which underwent in situ unfavored endo-trig cyclization upon treatment with NaH and secondary amines, to give 2-ethoxy-2-cyclopenetenones 27 and 28 and α-keto enamines 25 in good yield.The mechanism for the cyclization is discussed.
