GaCl3 Promoted one-step α,α-diethynylation and α,α-diethenylation reactions of silyl enol ethers
摘要:
In the presence of GaCl3 and 2,6-di(tert-butyl)-4-methylpyridine, alpha-monosubstituted silyl enol ethers were alpha,alpha-diethynylated with a chlorosilylacetylene in one step. An analogous reaction using a silylacetylene gave alpha,alpha-diethenylated ketones. (c) 2006 Elsevier Ltd. All rights reserved.
Solution Structures of Lithium Enolates of Cyclopentanone, Cyclohexanone, Acetophenones, and Benzyl Ketones. Triple Ions and Higher Lithiate Complexes
作者:Kristopher J. Kolonko、Margaret M. Biddle、Ilia A. Guzei、Hans J. Reich
DOI:10.1021/ja903479p
日期:2009.8.19
spectroscopic studies at low temperature (-110 to -150 degrees C) revealed that lithium p-fluorophenolate and the lithiumenolates of cyclohexanone, cyclopentanone and 4-fluoroacetophenone have tetrameric structures in THF/Et(2)O and THF/Et(2)O-HMPA by study of the effects of the addition of HMPA. The Z and E isomers of the lithiumenolate of 1,3-bis-(4-fluorophenyl)-2-propanone (5F-Li) show divergent behavior
Less highly substituted silyl enol ethers are regiospecifically prepared in high yield, around room temperature under kinetic conditions, from unsymmetrical cyclic ketones and magnesium bis(diisopropylamide) [(DA)2Mg] in THF/heptane. This high regioselectivity is markedly higher than these reported for bromomagnesium diisopropylamide (DAMgBr); it is also similar to this of LDA/DME at −78°C, but (DA)2Mg
Treatment of aliphatic carbonylcompounds with trimethylsilyl chloride with Mg turning for Grignard reaction without any pre-treatment in N,N-dimethylformamide at room temperature brought about highly facile, effective and stereoselective coupling to give the corresponding silylenolethers in good yields.
Stereoselective Synthesis of Trisubstituted Vinylboronates from Ketone Enolates Triggered by 1,3‐Metalate Rearrangement of Lithium Enolates
作者:Yue Hu、Wei Sun、Tao Zhang、Nuo Xu、Jianeng Xu、Yu Lan、Chao Liu
DOI:10.1002/anie.201909235
日期:2019.10.28
unprecedented stereoselectivesynthesis of trisubstituted vinylboronates is reported to proceed by direct borylation of lithium ketone enolates under transition-metal-free conditions. The stereospecific C-O borylation of lithium enolates was triggered by a carbonyl-induced 1,3-metalate rearrangement via a C-bound boron enolate. DFT calculations and control experiments revealed that the stereoselectivity is controlled
Highly Stereoselective Oxazaborolidinium Ion Catalyzed Synthesis of (<i>Z</i>)-Silyl Enol Ethers from Alkyl Aryl Ketones and Trimethylsilyldiazomethane
作者:Byung Chul Kang、Su Yong Shim、Do Hyun Ryu
DOI:10.1021/ol500174q
日期:2014.4.18
Highly stereoselective (Z)-silyl enol ethers were prepared fromalkylarylketones and trimethylsilyldiazomethane (TMSD) using an oxazaborolidinium ion catalyst. In addition, ring-expanded silyl enol ethers were successfully constructed from cyclic ketones. Their synthetic utilities were shown by sequential Mukaiyama aldol and [2 + 2]-cycloaddition reactions.