排序方式: 共有37条查询结果,搜索用时 15 毫秒
11.
JohnF. Bower InSu Kim RyanL. Patman MichaelJ. Krische 《Angewandte Chemie (International ed. in English)》2009,48(1):34-46
Classical protocols for carbonyl allylation, propargylation and vinylation typically rely upon the use of preformed allyl metal, allenyl metal and vinyl metal reagents, respectively, mandating stoichiometric generation of metallic byproducts. Through transfer hydrogenative C C coupling, however, carbonyl addition may be achieved from the aldehyde or alcohol oxidation level in the absence of stoichiometric organometallic reagents or metallic reductants. Here, we review transfer hydrogenative methods for carbonyl addition, which encompass the first catalytic protocols enabling direct C H functionalization of alcohols. 相似文献
12.
Highly Selective Manganese(I)/Lewis Acid Cocatalyzed Direct C−H Propargylation Using Bromoallenes
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Can Zhu Jonas Luca Schwarz Dr. Sara Cembellín Steffen Greßies Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2018,57(2):437-441
A manganese(I)/Lewis acid cocatalyzed direct C?H propargylation with high selectivity has been developed. BPh3 was discovered to not only promote the reactivity, but also enhance the selectivity. Secondary, tertiary, and even quaternary carbon centers at the propargylic position could be directly constructed. Both internal and terminal alkynes are easily accessible. The chirality was successfully transferred from an axially chiral allene to central chirality. The reactivity of the manganese catalyst in this reaction was found to be unique among transition metal catalysts. 相似文献
13.
《Mendeleev Communications》2022,32(2):218-220
An improved synthesis of (propargyl)nitramine and its pioneering conversion to di(propargyl)nitramine involve the alkylation of NH nitramines with propargyl halides or tosylate as the key steps. The standard (p° = 0.1 MPa) molar enthalpy of formation at 298.15 K for di(propargyl)nitramine was determined from the experimental standard molar energy of combustion in oxygen, measured by static bomb combustion calorimetry. Propargyl nitramines are suitable substrates for 1,3-dipolar cycloaddition reactions with azides, nitrile oxides and diazo compounds. 相似文献
14.
Efficient zinc-mediated allylation, propargylation, and benzylation of isatin-derived imines were undertaken for the synthesis of 3-substituted 3-aminooxindoles with ≈80% yield. Such alternative approach has efficiently avoided the use of catalysts, severe reaction conditions, multistep procedures, and reaction additives. For exploring and materializing the synthetic utility, different allyl, propargyl, and benzyl bromides were used for generalizing the synthetic route. The structure of the synthesized compounds was established and confirmed by 1H NMR, 13C NMR, FTIR, and mass spectroscopic techniques. 相似文献
15.
Dr. Laina M. Geary Joyce C. Leung Prof. Dr. Michael J. Krische 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(52):16823-16827
Under the conditions of ruthenium‐catalyzed transfer hydrogenation employing isopropanol as a source of hydrogen, isopropoxy‐substituted enyne 1 b and aldehydes 3 a – 3 l engage in reductive coupling to provide products of propargylation 4 a – 4 l with good to complete levels of anti‐diastereoselectivity. The unprotected tertiary hydroxy moiety of isopropoxy enyne 1 b is required to enforce diastereoselectivity. Deuterium‐labeling studies corroborate reversible enyne hydrometalation in advance of carbonyl addition. As demonstrated in the conversion of 4 f – h and 4 k to 5 f – h and 5 k , the isopropoxy group of the product is readily cleaved upon exposure to aqueous sodium hydroxide to reveal the terminal alkyne. 相似文献
16.
P. Srihari J. Shyam Sunder Reddy Dinesh C. Bhunia S. S. Mandal J. S. Yadav 《合成通讯》2013,43(9):1448-1455
Aryl‐propargylic alcohols undergo O‐, S‐, and N‐nucleophilic substitution reactions in the presence of a catalytic amount of PMA‐SiO2. 相似文献
17.
A highly stereoselective total synthesis of isocladosorpin is described. The key steps involved in this synthesis are oxa-Michael reaction, asymmetric propargylation, and Alder–Rickerts reaction. 相似文献
18.
Lingzi Peng Zhuozhuo He Xianghong Xu Chang Guo 《Angewandte Chemie (International ed. in English)》2020,59(34):14270-14274
A novel Ni/Cu dual catalysis gives rise to fundamentally new cooperative reactivity and enables the regio‐ and enantioselective propargylic alkylation reaction. A diverse set of α‐quaternary propargylated amino ester derivatives were synthesized in good yields with excellent enantioselectivity (up to 99 % ee). This work highlights the power of cooperative catalysis, which can be expected to have broad implications in homogeneous catalysis beyond the highly valuable synthetic intermediates. 相似文献
19.
The Renaissance of an Old Problem: Highly Regioselective Carboxylation of 2‐Alkynyl Bromides with Carbon Dioxide
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bukeyan Miao Gen Li Prof. Dr. Shengming Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17224-17228
A steric effect‐controlled, zinc‐mediated carboxylation of different 2‐alkynyl bromides under an atmospheric pressure of CO2 has been developed by careful tuning of different reaction parameters, including the metal, solvent, temperature, and additive. 2‐Substituted 2,3‐allenoic acids were afforded from primary 2‐alkynyl bromides, whereas the carboxylation of secondary 2‐alkynyl bromides yielded 3‐alkynoic acids in decent yields. A rationale for the observed regioselectivity has been proposed. 相似文献
20.
2 Deoxy D ribose (1) ,thesugarpartofDNA ,isoneofthemostimportantstartingmaterialnotonlyforthepreparationsofnucleosides ,nucleotides ,DNAandtheiranalogs,butalsoforthesynthesesofanumberofotherbio activecompounds .1Recentlyitsantipode 2 deoxy L ribose (2 )wasalsoattra… 相似文献