3968-86-3Relevant academic research and scientific papers
Highly efficient NHC-iridium-catalyzed β-methylation of alcohols with methanol at low catalyst loadings
Lu, Zeye,Zheng, Qingshu,Zeng, Guangkuo,Kuang, Yunyan,Clark, James H.,Tu, Tao
, p. 1361 - 1366 (2021/06/30)
The methylation of alcohols is of great importance since a broad number of bioactive and pharmaceutical alcohols contain methyl groups. Here, a highly efficient β-methylation of primary and secondary alcohols with methanol has been achieved by using bis-N-heterocyclic carbene iridium (bis-NHC-Ir) complexes. Broad substrate scope and up to quantitative yields were achieved at low catalyst loadings with only hydrogen and water as by-products. The protocol was readily extended to the β-alkylation of alcohols with several primary alcohols. Control experiments, along with DFT calculations and crystallographic studies, revealed that the ligand effect is critical to their excellent catalytic performance, shedding light on more challenging Guerbet reactions with simple alcohols. [Figure not available: see fulltext.].
Robust eco-friendly protocol for the preparation of γ-hydroxy- α,β-acetylenic esters by sequential one-pot elimination-addition of 2-bromoacrylates to aldehydes promoted by LTMP in 2-MeTHF
Pace, Vittorio,Castoldi, Laura,Alcantara, Andres R.,Holzer, Wolfgang
supporting information; experimental part, p. 1859 - 1863 (2012/08/14)
An efficient and widely applicable preparation of γ-hydroxy-α, β-acetylenic esters is described by means of a one-pot dehydrobromination of a 2-bromoacrylate ester with LTMP followed by the electrophilic addition of the transient propiolate to different aldehydes in the eco-friendly solvent 2-MeTHF. The Royal Society of Chemistry 2012.
Diamine-free lithiation-trapping of N-Boc heterocycles using s-BuLi in THF
Barker, Graeme,Obrien, Peter,Campos, Kevin R.
supporting information; experimental part, p. 4176 - 4179 (2010/11/16)
A diamine-free protocol for the s-BuLi-mediated lithiation-trapping of N-Boc heterocycles has been developed. In the optimized procedure, lithiation is accomplished using s-BuLi in THF at -30 °C for only 5 or 10 min. Subsequent electrophilic trapping or transmetalation-Negishi coupling delivered a range of functionalized pyrrolidines, imidazolidines, and piperazines in 43-83% yield.
Reaction of secondary and tertiary aliphatic halides with aromatic aldehydes mediated by chromium(II): a selective cross-coupling of alkyl and ketyl radicals
Wessjohann, Ludger A.,Schmidt, Gisela,Schrekker, Henri S.
, p. 2134 - 2142 (2008/09/18)
Takai-Utimoto reactions with secondary and tertiary aliphatic halides usually failed according to previous reports. Now, significant improvements could be achieved, and especially secondary aliphatic halides can be coupled to aromatic aldehydes in yields of up to >95%. A variety of processes are competing with the desired one, and thus conditions must be adapted to the nature of the aldehyde as well as the aliphatic halide used, as the outcome of these reactions is strongly affected by the putative radical intermediates.
The chromium(II)-mediated coupling of secondary alkylhalides with aromatic aldehydes
Wessjohann, Ludger A.,Schmidt, Gisela,Schrekker, Henri S.
, p. 2139 - 2141 (2008/02/09)
The scope of chromium(II)-mediated Takai-Utimoto reactions was extended to previously unconvertable secondary alkylhalides. Optimization allowed yields of up to over 95%. Georg Thieme Verlag Stuttgart.
Chiral α-branched benzylic carbocations: Diastereoselective intermolecular reactions with arene nucleophiles and NMR spectroscopic studies
Muehlthau, Friedrich,Stadler, Daniel,Goeppert, Alain,Olah, George A.,Prakash, G. K. Surya,Bach, Thorsten
, p. 9668 - 9675 (2007/10/03)
The chiral benzylic alcohols 1-6 were prepared and subjected to S N1-type displacement reactions with various arene nucleophiles in acidic medium. Under optimized conditions (HBF4·OEt 2, CH2Cl2, -78 °
Preparation of alcohols from sulfones and trialkylboranes
Billaud, Célia,Goddard, Jean-Philippe,Le Gall, Thierry,Mioskowski, Charles
, p. 4451 - 4454 (2007/10/03)
The reaction of sulfone anions with trialkylboranes followed by thermal isomerization of the obtained boron compounds in the presence of excess borane-methyl sulfide complex and by alkaline hydroperoxide oxidation yields primary alcohols.
A new method for alkylation of aromatic aldehydes using alkylboron chloride derivatives in the presence of oxygen
Kabalka, George W,Wu, Zhongzhi,Ju, Yuhong
, p. 3243 - 3248 (2007/10/03)
Reactions of aromatic aldehydes with alkylboron chloride derivatives in the presence of oxygen have been investigated. Dialkylboron chlorides react with aryl aldehydes to produce arylalkylmethanols in good to excellent yields. Under the same reaction conditions, alkylboron dichlorides lead to the formation of arylalkyl chlorides.
Alkylation of aromatic aldehydes with alkylboron chloride derivatives
Kabalka, George W,Wu, Zhongzhi,Ju, Yuhong
, p. 1663 - 1670 (2007/10/03)
The reaction of aryl aldehydes with alkylboron chlorides has been investigated. Monoalkylboron dichlorides react with aryl aldehydes in hexane under reflux conditions to give a mixture of dichloroarylmethane and benzyl chloride. Under the same reaction conditions, dialkylboron chlorides lead to formation of a mixture of benzyl chloride and the chloroalkylation product. In the presence of a base such as 2,6-lutidine, the reactions of monoalkylboron dichlorides with aryl aldehydes yield small amounts of the desired alkylation products at room temperature. Dialkylboron chlorides react with aryl aldehydes in hexane in the presence of base to generate the corresponding arylalkylmethanols in good yields.
Alkylation of aromatic aldehydes with boron halide derivatives
Kabalka, George W.,Wu, Zhongzhi,Trotman, Sarah E.,Gao, Xiao
, p. 255 - 256 (2007/10/03)
(matrix presented) Aryl aldehydes react with alkylboron chloride derivatives in the presence of base to generate the corresponding arylalkylmethanols in good yields. A variety of alkylboron chlorides can be utilized in the new alkylation reaction.
