A catalytic system consisting of vanadium oxyacetylacetonate [VO(acac)(2)] and 3 A molecular sieves (MS3A) in acetonitrile works effectively for the aerobic oxidation of propargylic alcohols [R(1)CH(OH)Ctbd1;CR(2)] to the corresponding carbonyl compounds under an atmospheric pressure of molecularoxygen. Although the reactivity of alpha-acetylenic alkanols (R(1) = alkyl) is lower compared to that of
Divergent Synthesis of Oxa‐Cyclic Nitrones through Gold(I)‐Catalyzed 1,3‐Azaprotio Transfer of Propargylic α‐Ketocarboxylate Oximes: Experimental and DFT Studies
α‐ketocarboxylate oximes, a new type of alkynyl oximes featuring an ester tether, has been explored by taking advantage of gold catalysis. The incorporation of an oxygen atom to the chain of alkynyl oximes led to the formation of two different oxa‐cyclicnitrones. It was found that internal alkynyl oximes with an E‐configuration deliver five‐membered nitrones, whereas terminal alkynyl oximes with an E‐configuration
Palladium-catalysed dehydration of propynyl alcohols with tin(II) chloride
作者:Yoshiro Masuyama、Jun P. Takahara、Kazumi Hashimoto、Yasuhiko Kurusu
DOI:10.1039/c39930001219
日期:——
α,γ-Disubstituted propynyl alcohols having a proton on 1-position of α-substituent have been dehydrated using PdCl2(PPh3)2 and SnCl2 in 1,3-dimethylimidazolidin-2-one under neutral conditions to produce 1,4-disubstituted (Z)-but-3-en-1 -ynes stereoselectively.
[3,3]-Sigmatropic rearrangements of propargyl alkynyl ethers. Synthesis of complex dienoates and unsaturated lactones
作者:Juan R. Sosa、Armen A. Tudjarian、Thomas G. Minehan
DOI:10.1039/d2ob02121h
日期:——
on low-temperature rearrangements of 1-alkynyl ethers, we describe herein the [3,3]-sigmatropic rearrangement of in situ formed propargyl alkynyl ethers to allenyl ketenes, which furnish complex tert-butyl-(2E,4Z)-dienoates 2 in good yields upon tert-butanol addition. Similarly, sigmatropic rearrangements of in situ formed propargyl lithioalkynyl ethers yield methyl-(2Z,4Z)-dienoates 4 upon methanol
在我们对 1-炔基醚的低温重排研究的扩展中,我们在本文中描述了原位形成的炔丙基炔基醚到联烯基乙烯酮的 [3,3]-σ 重排,其提供复杂的叔丁基-(2 E ,4 Z )-dienoates 2在加入叔丁醇后收率高。类似地,原位形成的炔丙基锂基炔基醚的 sigmatropic 重排在甲醇加成后产生甲基-(2 Z ,4 Z )-二烯酸酯4或在醛或酮加成丙二烯基炔诺酸酯中间体时产生不饱和内酯6 。
Selectivity in Organic Group Transfer in Reactions of Mixed Diorganomanganese(II) and Triorganomanganate(II) with 2-Cyclohexen-1-one or Cyclohexanecarbaldehyde
The unsymmetrical diorganomanganeses(II) (R1R2Mn) and magnesium triorganomanganates(II) (R12R2MnMgX) reacted with 2-cyclohexen-1-one to produce the 1,4-addition products in moderate to good yields. The approximate reactivity order obtained from the product distribution was CH2=CHCH2 > PhS > n-Bu > Ph > Me, Me3SiCH2, n-C6H13–C≡C. In contrast, the reactivity order for the addition of these reagents to
不对称二有机锰 (II) (R1R2Mn) 和三有机锰酸镁 (II) (R12R2MnMgX) 与 2-环己烯-1-one 反应生成 1,4-加成产物,收率适中。从产物分布获得的近似反应性顺序为 CH2=CHCH2 > PhS > n-Bu > Ph > Me、Me3SiCH2、n-C6H13–C≡C。相比之下,将这些试剂添加到环己烷甲醛的反应顺序是 CH2=CHCH2 > Ph > Me > n-Bu > n-C6H13C≡C > Me3SiCH2。