α-Triethylsilyl-α-diazoacetone in double cross-aldolisation: convenient acetone equivalent toward 5-hydroxy-1,3-diketones
摘要:
alpha-Triethylsilyl-alpha-diazoacetone underwent a sequential aldolisation-deprotection-aldolisation process to access the 2-diazo-3-oxo-1,5-dihydroxy skeleton with significant diversity. The diazo group could be efficiently removed by treatment with rhodium acetate to afford the corresponding 5-hydroxy-1,3-diketones. (c) 2012 Elsevier Ltd. All rights reserved.
Aldoladdition of α-triisopropylsilyl-α-diazoacetone (TIPS-diazoacetone), promoted by excess lithium diisopropylamide (LDA), was developed and applied to the synthesis of original C-TIPS diazoaldols, C-TIPS diazoketols, and a related Mannich-type product. An unprecedented mechanistic pathway has been proposed, involving a lithiated triazene intermediate resulting from the nucleophilic addition of LDA