Henderson.Kenneth - Charles E. Schmidt College of Science
Title: Use of Homochiral Magnesium Amides in Synthesis (co-PI). Source: ..... “ Magnesium amide base-mediated enantioselective deprotonation ... magnesium amide base and the observation of a novel kinetic resolution process” Henderson ,.
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Asymmetric Deprotonation - The Stoltz Group
Mar 28, 2005 ... Eames, "Recent Developments in Enantioselective Deprotonation Mediated by Sub-Stoichiometric Quantities ... Differentiated by Chiral Base. H. H. Li-amide. Base. (Additives). R. O .... Chiral Magnesium Amides in Ketone Deprotonation ..... Metal Exchange to Ti Leads to a Highly Diastereoselective Process.
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A. Organolithium Reagents
way either because the metalation process is too slow (i.e., proton not ... The hindered amide bases such as LDA show a much greater selectivity for ... are often preferred over n-butyllithium for the deprotonation of compounds which are susceptible .... Copper Reagents: “Copper(I) Catalyzed Reactions of Organolithium and ...
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ProPhenol-Catalyzed Asymmetric Additions by Spontaneously
Feb 4, 2015 ... direct deprotonation of three hydroxyl groups (Scheme 1). Both ... coordination sites on the catalyst, and mitigate base-mediated side reactions. The direct .... can be converted to the corresponding ester, amide, or ketone in a single step ... this process, the use of di-n-butylmagnesium, in place of diethylzinc ...
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View PDF Version - RSC Publishing - Royal Society of Chemistry
Mar 6, 2007 ... isomerization, halogen dance, or base catalyzed halogen dance. (BCHD). The overall ... deprotonation (metal–hydrogen exchange) and metal–halogen exchange ... optimized to effectively control the migration process (or prevent it ... Historically, the first bases applied were amide bases such as. KNH2 ...
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Magnesium-catalysed nitrile hydroboration - RSC Publishing - Royal
Oct 20, 2015 ... homogeneous processes performed under heavier alkaline earth catalysis are ... a deconvolution of basic reactivity patterns for this relatively ... of magnesium- catalysed ester reduction with HBpin,19a these ... and an amide species (D) formed by formal Mg–H insertion of .... Whereas the asymmetric unit.
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Enantioselective Synthesis with Lithium/(-)-Sparteine - iSites
Enantioselective Synthesis with Lithium/( - )-Sparteine Carbanion Pairs. Dieter Hoppe* and ..... Scheme Deprotonation of a prochlral CH acid ACH,B by a chiral base and ... Early attempts at (-)-sparteine-mediated nucleophilic alkylation of ... tively slow ligand exchange in dialkylmagnesium/( - )-sparteine ..... amides .
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Kapitel_01 1..9 - The Evans Group Homepage - Harvard University
predisposition for a highly selective enolization process; it must provide a ... deprotonation leads to the corresponding E- or Z- ester enolate, which upon reac - ... enolates (Z:E i 100) were achieved using either lithium and sodium amide bases ... The original reports on the asymmetric aldol reactions mediated by boron or.
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Get PDF (104K) - Wiley Online Library
base and nucleophile ligand transfers, 780 one‐electron ... opening, and ring closure process .... magnesium thiolates and amides, 318 .... chiral catalyzed asymmetric nucleophilic aromatic ... concerted metalation‐deprotonation mechanism,.
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Some Items of Interest to Process R&D Chemists and Engineers
Sep 1, 2010 ... mediates for the regioselective preparation of substituted double bonds. Several ... TMP-derived magnesium amide bases. The resulting ...
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Aug 29, 2010 ... Deprotonation vs. halogen metal exchange - selectivity ..... Using phenyl copper reductive cupration of Ar-SO2R (pseudohalides) catalysed by Co: ... thermodynamic deprotonation using hindered lithium/magnesium amide bases: ..... Process route for Bristol-Myers Squibb (Rouhi Chem. .... Asymmetric DoM.
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Cobalt mediated [2+2+2] reactions (Volhardt reaction). – Ring Closing ..... thermodynamic deprotonation using hindered lithium/magnesium amide bases: .... 2. CuLi): – Aryl cuprates are less basic and more nucleophilic than aryl lithiums. .... General process is sometimes known as KUMADA-NEGISHI cross- coupling.
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LiCl-Mediated Direct Insertion of Magnesium Into Aryl, Heteroaryl
Direct Insertion of Magnesium in the Presence of LiCl and ZnCl2, Chem. ... Directed Deprotonation Using Magnesium Amide Bases. ..... In 1995 Overman and coworkers published an enantioselective total synthesis of (–)- ... More recently, in 2007 process chemists at Johnson & Johnson have developed an improved.
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Cooperative catalysis by carbenes and Lewis acids in a highly
Jul 18, 2010 ... In many biochemical processes, different catalytic species, such as Lewis acids and bases, ... amide bonds by making use of a serine or cysteine (Lewis base), an aspartic ... and demonstrate its utility with the highly enantioselective addition .... The azolium precatalyst is deprotonated by the base (TBD) and.
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Synergistic catalysis - Princeton University
Jan 25, 2012 ... processes, such as strong complexation of a Lewis acid and a Lewis base or a ... combinations. For example, many Lewis acids and Lewis bases ... esters (3), amides (4), and phosphonates (5) in high yield and selectivity. ... Scheme 1 Rhodium- and palladium-catalyzed enantioselective allylic alkylation of ...
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Chapter 13-1 Chem 66H Organometallic Reagents: Grignard
and magnesium. Since the .... The acetylide ion may be formed by such strong bases as —:NH2 (pKa. 33), RMgX or .... Chem 66H. Palladium Catalyzed Carbon -Carbon Bond Formation ... bond breaking processes in the gas phase. Each of ..... amides. NaBH4 sodium borohydride reduces only aldehydes and ketones: more.
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TITLE (Word Style “A_Title”) - Arkivoc
The 2-lithiation of the furan ring, achieved by direct deprotonation with an alkylithium .... precursor in a synthesis of chiral ligands for asymmetric catalysis ( Scheme 5).53 .... The DoM process, combined to the use of a lithium amide base such as .... iodination and subsequent palladium-catalyzed cross-coupling reactions.123.
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Chiral Ca-, Sr-, and Ba-Catalyzed Asymmetric Direct-Type Aldol
Brønsted base-mediated reactions, use of a catalytic amount of base is preferred ... aldol process (for a general review of asymmetric aldol reactions, see [11, 12]), ... The Brønsted basicity is used for deprotonation of acidic protons, such as ..... preparation of chiral catalysts, it was also found that calcium amide (e.g., Ca.
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An enantioselective, modular, and general route to the cytochalasins
Aug 17, 2004 ... toward the functioning of HIV protease, and toward the process of ... 2, inter- mediates 4 and 9). In addition .... selective deprotonation of the ketone 17 was accomplished by using potassium bis(trimethylsilyl)amide (KHMDS) as base; addition .... formed into L-696,474 (2) after exposure to magnesium sulfate.
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Download (422kB) - Strathprints - University of Strathclyde
Apr 17, 2014 ... enantioselective deprotonation of 4-alkylcyclohexanones. ... with a bis-amide mono-alkyl compound (and a tris-alkyl lithium ... This LiCl-containing base was used to ... £250000 per year per batch tonne process.2 Therefore one priority in .... was obtained when the dialkylmagnesium (Me3SiCH2)2Mg was.
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