31254-19-0Relevant academic research and scientific papers
Synergistic Relay Reactions To Achieve Redox-Neutral α-Alkylations of Olefinic Alcohols with Ruthenium(II) Catalysis
Kan, Jian,Li, Chao-Jun,Li, Chen-Chen,Li, Jianbin,Lv, Leiyang,Qiu, Zihang
, p. 4544 - 4549 (2020/02/04)
Herein, we report a ruthenium-catalyzed redox-neutral α-alkylation of unsaturated alcohols based on a synergistic relay process involving olefin isomerization (chain walking) and umpolung hydrazone addition, which takes advantage of the interaction between the two rather inefficient individual reaction steps to enable an efficient overall process. This transformation shows the compatibility of hydrazone-type “carbanions” and active protons in a one-pot reaction, and at the same time achieves the first Grignard-type nucleophilic addition using olefinic alcohols as latent carbonyl groups, providing a higher yield of the corresponding secondary alcohol than the classical hydrazone addition to aldehydes does. A broad scope of unsaturated alcohols and hydrazones, including some complex structures, can be successfully employed in this reaction, which shows the versatility of this approach and its suitability as an alternative, efficient means for the generation of secondary and tertiary alcohols.
I2/Li2CO3-promoted cyanation of diarylalcohols through a dual activation process
Hu, Liangzhen,Hussain, Muhammad Ijaz,Deng, Qingfu,Liu, Qing,Feng, Yangyang,Zhang, Xiaohui,Xiong, Yan
, p. 308 - 314 (2018/12/11)
One-step base promoted strategy for cyanation of α,α-diaryl alcohols has been developed under mild and transition metal-free conditions. This method provides a straightforward and facile way towards the synthesis of β,γ-unsaturated nitriles and α-phenylnitiriles from α-vinyl carbinols and α,α-diaryl methanols, respectively, up to 99% yield. Moreover, various azides and ethers could also be accessed from their respective nucleophiles under standard reaction conditions.
Additions of Organomagnesium Halides to α-Alkoxy Ketones: Revision of the Chelation-Control Model
Read, Jacquelyne A.,Yang, Yingying,Woerpel
supporting information, p. 3346 - 3349 (2017/07/13)
The chelation-control model explains the high diastereoselectivity obtained in additions of organometallic nucleophiles to α-alkoxy ketones but fails for reactions of allylmagnesium halides. Low diastereoselectivity in ethereal solvents results from no chelation-induced rate acceleration. Additions of allylmagnesium bromide to carbonyl compounds are diastereoselective using CH2Cl2 as the solvent even though rate acceleration is still absent. Stereoselectivity likely arises from the predominance of the chelated form in solution. Therefore, a revised chelation-control model is proposed.
Iron-promoted difunctionalization of alkenes by phenylselenylation/1,2-aryl migration
Wu, Ping,Wu, Kaikai,Wang, Liandi,Yu, Zhengkun
supporting information, p. 5450 - 5453 (2017/11/06)
Iron-promoted difunctionalization of α,α-diaryl and α-aryl-α-alkyl allylic alcohols has been efficiently achieved by means of N-(phenylseleno)phthalimide (N-PSP) under mild conditions. An in situ generated phenylselenium cation (PhSe+) was added to the ol
Organoselenium-catalyzed, hydroxy-controlled regio- and stereoselective amination of terminal alkenes: Efficient synthesis of 3-amino allylic alcohols
Deng, Zhimin,Wei, Jialiang,Liao, Lihao,Huang, Haiyan,Zhao, Xiaodan
supporting information, p. 1834 - 1837 (2015/04/27)
An efficient route to prepare 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of bases by orangoselenium catalysis has been developed. In the absence of bases α,β-unsaturated aldehydes were formed in up to 97% yield. Control experiments reveal that the hydroxy group is crucial for the direct amination.
Enantioselective construction of all-carbon quaternary centers by branch-selective Pd-catalyzed allyl-allyl cross-coupling
Zhang, Ping,Le, Hai,Kyne, Robert E.,Morken, James P.
supporting information; experimental part, p. 9716 - 9719 (2011/08/04)
The Pd-catalyzed cross-coupling of racemic tertiary allylic carbonates and allylboronates is described. This reaction generates all-carbon quaternary centers in a highly regioselective and enantioselective fashion. The outcome of these reactions is consistent with a process that proceeds by way of 3,3′-reductive elimination of bis(η1-allyl)palladium intermediates. Strategies for distinguishing the product alkenes and application to the synthesis of (+)-α-cuparenone are also described.
Rhenium-catalyzed 1,3-isomerization of allylic alcohols: Scope and chirality transfer
Morrill, Christie,Beutner, Gregory L.,Grubbs, Robert H.
, p. 7813 - 7825 (2007/10/03)
(Chemical Equation Presented) The scope of the triphenylsilyl perrhennate (O3ReOSiPh3, 1) catalyzed 1,3-isomerization of allylic alcohols has been thoroughly explored. It was found to be effective for a wide variety of secondary and tertiary allylic alcohol substrates bearing aryl, alkyl, and cyano substituents. Two general reaction types were found which gave high levels of product selectivity: those driven by formation of an extended conjugated system and those driven by selective silylation of a particular isomer. The efficiency of chirality transfer with various substrates was investigated, and conditions were found in which secondary and tertiary allylic alcohols could be formed with high levels of enantioselectivity. Consideration of selectivity trends with respect to the nature of the substituents around the allylic system revealed that this is a reliable and predictable method for allylic alcohol synthesis.
Vilsmeier Reaction on Some 1-Alkyl-1-arylallyl Alcohols: Benzannulation Leading to Biphenyl-mono- and Dicarboxaldehydes
Rao, M. Suresh Chander,Rao, G. S. Krishna
, p. 213 - 216 (2007/10/02)
1,1-Disubstituted alkylarylallyl alcohols (2a-d) have been prepared from alkyl aryl ketones (1a-d) by Grignard reaction with vinylmagnesium bromide and subjected to the action of phosphoryl chloride in dimethylformamide under Vilsmeier reaction conditions.The biphenyl-mono- (3a-d) and dicarboxaldehydes (4a-d) formed have been readily separated and fully characterized.
The synthesis and characterization of 3,3-disubstituted pent-4-enals and their 2,2-(trimethylendithio)pent-4-enal precursors, including the X-ray crystal structure of (R)-3-ethyl-3-phenyl-2,2-(trimethylenedithio)pent-4-enal
Young, Charles G.,James, Brian R.,Rettig, Steven J.
, p. 1035 - 1040 (2007/10/02)
A variety of 3,3-disubstituted pent-4-enals (5a, R=Me, R'=Et; 5b, R=Me, R'=Ph; 5c, R=Et, R'=Ph) has been prepared by the Raney nickel desulfurization of the corresponding 3,3-disubstituted 2,2-(trimethylenedithio)pent-4-enal precursors 4a-4c.The precursor compounds were prepared by the alkylation of 2-formyl-1,3-dithiane with the appropriate 3,3-disubstituted allylic bromide.The new compounds have been characterized by elemental analysis, infrared and nmr spectroscopy, and mass spectrometry.The crystal and molecular structure of (R)-4c has also been determined by X-ray crystallography.At temperatures of ca. 130 deg C, compounds 4a-4c undergo intramolecular rearrangement to form the trisubstituted alkenes 6a-6c, which have also been characterized by the present study.
