Isomerization of Propargylic Alcohols into α,β-Unsaturated Carbonyl Compounds Catalyzed by the Sixteen-Electron Allyl-Ruthenium(II) Complex [Ru(η3-2-C3H4Me)(CO)(dppf)][SbF6]
作者:Victorio Cadierno、Sergio E. García-Garrido、José Gimeno
DOI:10.1002/adsc.200505294
日期:2006.1
(η3-allyl)-ruthenium(II) complex [Ru(η3-2-C3H4Me)(CO)(dppf)][SbF6] is an efficient catalyst for the regioselective isomerization of terminal propargylic alcohols HCCCR1R2(OH) into α,β-unsaturatedaldehydes R1R2CCHCHO or ketones R3R4CC(R1)COMe (if R2=CHR3R4) under mild conditions. This complex has been also used as catalyst for the preparation of conjugated 1,3-enynes via dehydration of propargylic alcohols
16-E -(η 3 -烯丙基) -钌(II)配合物的[Ru(η 3 -2-C 3 H ^ 4 ME)(CO)(DPPF)] [的SbF 6 ]是用于区域选择性异构化的有效催化剂在温和条件下将末端炔丙醇HCCCR 1 R 2(OH)转变为α,β-不饱和醛R 1 R 2 CCHCHO或酮R 3 R 4 CC(R 1)COMe(如果R 2 = CHR 3 R 4)。这种复杂的也已用作催化剂用于制备缀合的1,3-烯炔的经由 炔丙醇的脱水。
Decarboxylative Nazarov Cyclization-Based Chirality Transfer for Asymmetric Synthesis of 2-Cyclopentenones
Asymmetricsynthesis of 2-cyclopentenones was achieved by chirality transfer based on Lewis acid catalyzed decarboxylative Nazarov cyclization of opticallyactive cyclic enol carbonates, which are prepared by silver-catalyzed carbon dioxide incorporation into optically pure propargyl alcohols. The stereochemistry at the 4,5-positions of the 2-cyclopentenones was cleanly constructed by reflecting the
Cycloadditions of Allylsilanes, Part 11. Stereoselective Synthesis of Hydroxycyclopentanes and Hydroxymethylcyclobutanes by Titanium Tetrachloride-Promoted [3+2] and [2+2] Cycloadditions of Sterically Hindered Allylsilanes and Subsequent Oxidative Cleavage of the Carbon-Silicon Bond
作者:Hans-Joachim Knölker、Peter G. Jones、Günter Wanzl
DOI:10.1055/s-1998-1727
日期:1998.6
Even highly sterically hindered organosilicon compounds containing the bulky tert-butyldiphenylsilyl group can be oxidatively cleaved to the corresponding carbinols using a modified protocol of the original Fleming-Tamao oxidation that generates the intermediate tert-butyldifluorosilyl derivatives. This novel application emphasizes the utility of allyl-tert-butyldiphenylsilane as a building block for the stereoselective synthesis of either hydroxycyclopentanes or hydroxymethylcyclobutanes via the sequence titanium tetrachloride-promoted cycloaddition and oxidative cleavage.