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Laëtitia Palais Alexandre Alexakis Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(40):10473-10485
SimplePhos ligands represent a novel class of monodentate chiral ligands based on a chiral amine moiety and flexible diaryl groups on the phosphorous atom. They can be easily prepared by two different pathways and they can be highly functionalised. Herein we report the copper‐catalysed asymmetric conjugate addition of diethyl zinc and trialkylaluminium reagents with SimplePhos ligands, which gives high enantioselectivity with cyclic enones, acyclic enones and nitro‐olefins, with up to 98.6 % ee. Of particular interest is the reaction of trialkylaluminium reagents with a wide range of 3‐substituted enones, thus allowing the formation of stereogenic quaternary carbon centres. 相似文献
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Hak‐Suk Sim Xinhui Feng Jaesook Yun Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(8):1939-1943
Josi or Mandy? Asymmetric conjugate addition of diboron to acyclic enones catalyzed by copper affords chiral organoboronates that possess a boronate group at the β stereocenter with excellent chemical yields and enantioselectivities (see scheme). This method accommodates the structural variation of acyclic enones and provides access to highly functionalized chiral organoboronates in one step.
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Jingjing Yao Prof. Dr. Xiaohua Liu Peng He Yin Zhu Xiangjin Lian Dr. Lili Lin Prof. Dr. Xiaoming Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16424-16430
Chiral N,N′‐dioxide/Zn(NTf2)2 complexes were demonstrated to be highly effective in the direct asymmetric conjugate addition of arylacetonitriles to alkylidene malonates under mild conditions. A wide range of substrates were tolerated to afford their corresponding products in moderate‐to‐good yields with high diastereoselectivities (82:18–>99:1 d.r.) and enantioselectivities (81–99 % ee). The reactions performed well, owing to the high Lewis acidity of the metal triflimidate and a ligand‐acceleration effect. The N,N′‐dioxide also benefited the deprotonation process as a Brønsted base. The catalytic reaction could be performed on the gram‐scale with retention of yield, diastereoselectivity, and enantioselectivity. The products that contained functional groups were ready for further manipulation. In addition, a possible catalytic model was proposed to explain the origin of the asymmetric induction. 相似文献
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Dr. Matthieu Tissot Prof. Alexandre Alexakis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(34):11352-11363
The copper‐catalysed conjugate addition of trialkylaluminium and dialkylzinc reagents to polyconjugated nitroolefins (nitrodiene and nitroenyne derivatives) is reported. A reversed Josiphos ligand L7 allows for the selective 1,4‐ or 1,6‐addition with high enantioselectivities. 相似文献
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Wenbin Mao Weichao Xue Elisabeth Irran Martin Oestreich 《Angewandte Chemie (International ed. in English)》2019,58(31):10723-10726
A new application of silicon Grignard reagents in C(sp3)?Si bond formation is reported. With the aid of BF3?OEt2, these silicon nucleophiles add across alkenes activated by various azaaryl groups under copper catalysis. An enantioselective version employing benzoxazole‐activated alkenes as substrates and a CuI‐josiphos complex as catalyst has been developed, forming the C(sp3)?Si bond with good to high enantiomeric ratios (up to 97:3). The method expands the toolbox for “conjugate addition” type C(sp3)?Si bond formation. 相似文献
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Copper‐Catalyzed Asymmetric Conjugate Addition of Dimethylzinc to Acyl‐N‐methylimidazole Michael Acceptors: a Powerful Synthetic Platform 下载免费PDF全文
Sammy Drissi‐Amraoui Dr. Marie S. T. Morin Dr. Christophe Crévisy Dr. Olivier Baslé Dr. Renata Marcia de Figueiredo Dr. Marc Mauduit Prof. Dr. Jean‐Marc Campagne 《Angewandte Chemie (International ed. in English)》2015,54(40):11830-11834
An efficient copper‐catalyzed enantioselective conjugate addition of dimethylzinc to α,β‐ and α,β,γ,δ‐unsaturated 2‐acyl‐N‐methylimidazoles has been achieved using a chiral bidentate hydroxyalkyl‐NHC ligand. The reactions proceeded with both excellent regio‐ and enantioselectivity (14 examples, 87–95 % ee) to afford the desired 1,4‐adducts, which were easily transformed to the corresponding aldehydes, esters, and ketones. Subsequently, this powerful methodology was therefore successfully applied in the synthesis of natural products. Furthermore, an iterative process was also disclosed leading to highly desirable 1,3‐desoxypropionate skeletons (up to 94 % d.e.). 相似文献
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Dr. Daniel Müller Prof. Alexandre Alexakis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(45):15226-15239
Alkenylaluminums undergo asymmetric copper‐catalyzed conjugate addition (ACA) to β‐substituted enones allowing the formation of stereogenic all‐carbon quaternary centers. Phosphinamine–copper complexes proved to be particularly active and selective compared with phosphoramidite ligands. After extensive optimization, high enantioselectivities (up to 96 % ee) were obtained for the addition of alkenylalanes to β‐substituted enones. Two strategies for the generation of the requisite alkenylaluminums were explored allowing for the introduction of aryl‐ and alkyl‐substituted alkenyl nucleophiles. Moreover, alkyl‐substituted phosphinamine (SimplePhos) ligands were identified for the first time as highly efficient ligands for the Cu‐catalyzed ACA. 相似文献
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Copper‐Catalyzed Tandem Hydrocupration and Diastereo‐ and Enantioselective Borylalkyl Addition to Aldehydes 下载免费PDF全文
Won Jun Jang Prof. Jaesook Yun 《Angewandte Chemie (International ed. in English)》2018,57(37):12116-12120
We report the copper‐catalyzed stereoselective addition of in situ generated chiral boron‐α‐alkyl intermediates to various aldehydes including α,β‐unsaturated aldehydes under mild conditions. This tandem and multicomponent method facilitated the synthesis of enantiomerically enriched 1,2‐hydroxyboronates bearing contiguous stereocenters in good yield with high diastereo‐ and enantioselectivity up to a ratio greater than 98:2. In particular, α,β‐unsaturated aldehydes were successfully used as electrophiles in Cu?H catalysis through 1,2‐addition without significant reduction. The resulting 1,2‐hydroxyboronates were used in various transformations. 相似文献
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Dr. Andreas Ole Termath B. Sc. Hanna Sebode M. Sc. Waldemar Schlundt Dr. René T. Stemmler Dr. Thomas Netscher Priv.‐Doz. Dr. Werner Bonrath Prof. Dr. Hans‐Günther Schmalz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(38):12051-12055
By introducing a disposable activating substituent at C‐3, the asymmetric 1,4‐addition to a notoriously unreactive 2‐substituted chromenone was achieved with high levels of (2R)‐stereoselectivity in the presence of a chiral CuI‐phosphoramidite complex as a catalyst. This paved the way for an efficient and conceptually novel synthesis of (R,R,R)‐α‐tocopherol from readily available starting materials. 相似文献
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Enantioselective Synthesis of Allylboronates and Allylic Alcohols by Copper‐Catalyzed 1,6‐Boration 下载免费PDF全文
Dr. Yunfei Luo Iain D. Roy Amaël G. E. Madec Prof. Hon Wai Lam 《Angewandte Chemie (International ed. in English)》2014,53(16):4186-4190
Chiral secondary allylboronates are obtained in high enantioselectivities and 1,6:1,4 ratios by the copper‐catalyzed 1,6‐boration of electron‐deficient dienes with bis(pinacolato)diboron (B2(pin)2). The reactions proceed efficiently using catalyst loadings as low as 0.0049 mol %. The allylboronates may be oxidized to the allylic alcohols, and can be used in stereoselective aldehyde allylborations. This process was applied to a concise synthesis of atorvastatin, in which the key 1,6‐boration was performed using only a 0.02 mol % catalyst loading. 相似文献
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A new sterically hindered chiral P,N‐ligand was synthesized and successfully applied to copper catalyzed asymmetric addition of diethylzinc to aromatic aldehydes. Various aromatic aldehydes can react smoothly to give the corresponding addition products with good to excellent enantioselectivities, which provides a readily accessible method for the preparation of chiral secondary alcohols. 相似文献
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Enantioselective Addition of Diethylzinc to Benzaldehyde by Catalysts of Chiral Heterocyclic Ligands
TheenantioselectiveadditionofdiethylzincreagentstoprochiralcarbonylgrouphasbeenachievedprincipallybycatalyticalamountofchiralP-aminoalcoholswhichhaveproventobehighlyeffectivecatalysts'.Ahydroxylgrouphasbeenregardedtobenecessaryforthechiralligandtoformazincalkoxideasthecatalyticspecies'.Wewishtoreporthereinontheethylationofbenzaldehydewithdiethylzincpromotedbyseveralkindsofoxazolidineandthiazolidinederivativeswhichdonotcontainhydroxylgroup.Fourkindschiralheterocyclicligandsweusedarelistedasfoll… 相似文献