A simple method for the conversion of propargyl alcohols to symmetrical 1,5-diynes using low valent titanium reagents
摘要:
Reaction of propargyl alcohols with low valent titanium species, prepared using the TiCl4/Et3N and TiCl4/Zn reagent systems, gives the corresponding symmetrical 1,5-diynes in 56-74% yields. (c) 2006 Elsevier Ltd. All rights reserved.
The fluoride reagents, TBAH2F3 and TBAHF2 (TBA: tetrabutylammonium), are found to catalyze the reactions of hexamethyldisilane with 1,3-dienes, aliphatic aldehydes, and aromatic aldehydes to give 1,4-disilyl-2-butenes, α-silyl alcohols and pinacols, respectively. Using an equimolar amount of TBAHF2 and disilanes, reduction of carbonyl compounds occurs in place of the silyl group addition.
Me<sub>2</sub>Zn-Mediated Addition of Acetylenes to Aldehydes and Ketones
作者:Pier Giorgio Cozzi、Jens Rudolph、Carsten Bolm、Per-Ola Norrby、Claudia Tomasini
DOI:10.1021/jo050115r
日期:2005.7.1
Contrary to expectations, commercially available 2 M Me2Zn in toluene is able to promote the addition of phenylacetylene to aldehydes and ketones. This reactivity is determined by a new, unprecedented mechanism, which involves activation of the zinc reagent via coordination with carbonyl substrates that behave “ligand like”. Broad scope, high tolerance to functional groups, and a simple procedure make
与预期相反,在甲苯中可商购的2 M Me 2 Zn能够促进将苯乙炔添加到醛和酮中。这种反应性是由一种新的,前所未有的机制决定的,该机制涉及通过与表现为“配体样”的羰基底物的配位来激活锌试剂。宽泛的范围,对官能团的高度耐受性以及简单的操作步骤使这种新方法对于合成化学家而言非常有趣。
Chiral Macrocycle-Catalyzed Highly Enantioselective Phenylacetylene Addition to Aliphatic and Vinyl Aldehydes
作者:Zi-Bo Li、Tian-Dong Liu、Lin Pu
DOI:10.1021/jo070091j
日期:2007.6.1
The 1,1‘-binaphthyl macrocycle (S)-2 is found to be an excellent catalyst for the alkyne addition to aldehydes. In the presence of (S)-2 (20 mol %) and Me2Zn (2 equiv) in THF at room temperature, the addition of phenylacetylene to linear or branched aliphatic aldehydes and vinylaldehydes gave various propargylic alcohols with 89−96% ee.
Highly Enantioselective Phenylacetylene Additions to Both Aliphatic and Aromatic Aldehydes
作者:Ge Gao、David Moore、Ru-Gang Xie、Lin Pu
DOI:10.1021/ol026921r
日期:2002.11.1
The readilyavailable and inexpensive BINOL in combination with Ti(O(i)Pr)(4) is found to catalyze the reaction of an alkynylzinc reagent with various types of aldehydes including aliphaticaldehydes, aromaticaldehydes, and other alpha,beta-unsaturated aldehydes to generate chiral propargyl alcohols with 91-99% ee at room temperature. No previous chiral catalysts have exhibited such a broad scope
Ligand-Promoted, Copper Nanoparticles Catalyzed Oxidation of Propargylic Alcohols with TBHP or Air as Oxidant
作者:Xiaoquan Yao、Chengyan Han、Min Yu、Weijiang Sun
DOI:10.1055/s-0030-1261227
日期:2011.10
A highly efficient oxidation of propargylicalcohols to ynones was catalyzed by copper nanoparticles (Cu Nps) with TBHP as an oxidant at room temperature. With bipyridine as the ligand, the reaction was accelerated significantly and led in good to excellent yields to a variety of propargylicalcohols. Furthermore, with Cu Nps as the catalyst, molecular oxygen in air could be utilized as oxidant effectively