Synthesis of Vinyl-, Allyl-, and 2-Boryl Allylboronates via a Highly Selective Copper-Catalyzed Borylation of Propargylic Alcohols
作者:Lujia Mao、Rüdiger Bertermann、Katharina Emmert、Kálmán J. Szabó、Todd B. Marder
DOI:10.1021/acs.orglett.7b03294
日期:2017.12.15
An efficient methodology for the synthesis of vinyl-, allyl-, and (E)-2-boryl allylboronates from propargylic alcohols via Cu-catalyzed borylation under mild conditions is reported. In the presence of commercially available Cu(OAc)2 or Cu(acac)2 and Xantphos, the reaction affords the desired products in up to 92% yield with a broad substrate scope (43 examples). Isolation of an allenyl boronate as
Tetraalkllleads (R4Pb) reacted quite smoothly with aldehydes R′CHO in the presence of TiCl4 to produce the corresponding alcohols (RCHOHR′) in high to good yields. The reagent system, R4Pb/TiCl4, exhibited high chemoselectivity; only aldehydes underwent the alkylation in the presence of ketones. Further, the newreagent exhibited high 1,2- and 1,3-asymmetric induction. The transfer order of alkyl groups
Iron-Catalyzed Aerobic Oxidation of Alcohols: Lower Cost and Improved Selectivity
作者:Xingguo Jiang、Jinxian Liu、Shengming Ma
DOI:10.1021/acs.oprd.8b00374
日期:2019.5.17
oxidation reaction of alcohols toward aldehydes or ketones using catalytic amounts of Fe(NO3)3·9H2O, 4-OH-TEMPO, and NaCl has been developed. Compared with the former catalytic system with TEMPO developed in this group, the new protocol using 4-OH-TEMPO, which is much cheaper on an industrial scale, accomplished the transformation with a higher selectivity, especially for aliphatic alcohols toward aldehydes
Highly Diastereoselective Synthesis of Cyclopentenones via a One-Pot Gold Catalysis, Nazarov Cyclization and Alkylation Cascade
作者:Long-Wu Ye、Meng-Qi Liu、Ai-Hua Zhou、Shuang Jiang、Jia-Qi Wang
DOI:10.1055/s-0033-1341204
日期:——
transformations [gold-catalyzed tandem reaction, scandium(III) trifluoromethanesulfonate catalyzed Nazarov cyclization, alkylation reaction] in a one-pot process led to the formation of cyclopentenonederivatives in excellent diastereoselectivities and moderate to good overall yields. Starting from readily available propargylic carboxylates, three sequential transformations [gold-catalyzed tandem reaction
Highly enantioselective addition of linear alkyl alkynes to linear aldehydes
作者:Yuhao Du、Mark Turlington、Xiang Zhou、Lin Pu
DOI:10.1016/j.tetlet.2010.07.082
日期:2010.9
It is discovered that the use of biscyclohexylamine (Cy(2)NH) as an additive can greatly enhance the enantioselectivity for the reaction of linear alkyl alkynes with linear aldehydes. The combination of (S)-BINOL (20 mol %), Cy(2)NH (5 mol %), ZnEt(2) (2 equiv), and Ti(O(i)Pr)(4) (0.5 equiv) catalyzes the reaction at room temperature in diethyl ether solution with 81-89% ee and 57-77% yield. (C) 2010 Elsevier Ltd. All rights reserved.