- Preparation of γ-siloxyallyltributylstannanes and their use in the synthesis of (±)-1-deoxy-6,8a-di-epi-castanospermine
-
γ-Siloxyallyltributylstannanes were selectively obtained as E or Z isomers from β-tributylstannylacrolein upon reaction with lithium or magnesium alkylcyanocuprates. The ability of the reagents to give a high syn selectivity when added to iminium salts ha
- Chevallier, Floris,Le Grognec, Erwan,Beaudet, Isabelle,Fliegel, Florian,Evain, Michel,Quintard, Jean-Paul
-
-
Read Online
- A Simple, Broad-Scope Nickel(0) Precatalyst System for the Direct Amination of Allyl Alcohols
-
The preparation of allylic amines is traditionally accomplished by reactions of amines with reactive electrophiles, such as allylic halides, sulfonates, or oxyphosphonium species; such methods involve hazardous reagents, generate stoichiometric waste streams, and often suffer from side reactions (such as overalkylation). We report here the first broad-scope nickel-catalysed direct amination of allyl alcohols: An inexpensive NiII/Zn couple enables the allylation of primary, secondary, and electron-deficient amines without the need for glove-box techniques. Under mild conditions, primary and secondary aliphatic amines react smoothly with a range of allyl alcohols, giving secondary and tertiary amines efficiently. This “totally catalytic” method can also be applied to electron-deficient nitrogen nucleophiles; the practicality of the process was demonstrated in an efficient, gram-scale preparation of the calcium antagonist drug substance flunarizine (Sibelium).
- Sweeney, Joseph B.,Ball, Anthony K.,Lawrence, Philippa A.,Sinclair, Mackenzie C.,Smith, Luke J.
-
supporting information
p. 10202 - 10206
(2018/08/06)
-
- Simple and efficient synthesis of N-alkyl and N-aryl succinimides in hot water
-
A new, simple synthesis of succinimides is described. The reactions were carried out under the ultimate green conditions excluding both catalyst and organic solvent by applying simple stirring at 100 °C. A wide variety of N-susbstituted succinimides have been prepared in high yields by using succinic acid and primary amines in hot water. Yield of N-alkyl substituted succinimides were found to be higher than those of N-aryl substituted succinimides.
- Bozdo?an, Burcu,Er?at?r, Mehmet,Demirkol, Onur,Akba?lar, Dilek,Giray, E. Sultan
-
p. 217 - 223
(2017/01/22)
-
- Chemo- And diastereoselectivities in the electrochemical reduction of maleimides
-
The electrochemical cathodic reduction of cyclic imides (maleimides) to succinimides can be achieved chemoselectively in the presence of alkene, alkyne, and benzyl groups. The efficiency of the system was demonstrated by using a 3D electrode in a continuous flow reactor. The reduction of 3,4-dimethylmaleimides to the corresponding succinimides proceeds with a 3:2 diastereomeric ratio, which is independent of the nitrogen substituent and electrode surface area. The stereoselectivity of the process was rationalized by using DFT calculations, involving an acid-catalyzed tautomerization of a half-enol occurring through a double hydrogen-transfer mechanism.
- Rix, Kathryn,Kelsall, Geoffrey H.,Hellgardt, Klaus,Hii, King Kuok
-
p. 665 - 671
(2015/03/04)
-
- Asymmetric bioreduction of activated carbon-carbon double bonds using Shewanella yellow enzyme (SYE-4) as novel enoate reductase
-
Shewanella yellow enzyme (SYE-4), a novel recombinant enoate reductase, was screened against a variety of different substrates bearing an activated double bond, such as unsaturated cyclic ketones, diesters, and substituted imides. Dimethyl- and ethyl esters of 2-methylmaleic acid were selectively reduced to (R)-configured succinic acid derivatives and various N-substituted maleimides furnished the desired (R)-products in up to >99% enantiomeric excess. Naturally occurring (+)-carvone was selectively reduced to (-)-cis- dihydrocarvone and (-)-carvone was converted to the diastereomeric product, respectively. Overall SYE-4 proved to be a useful biocatalyst for the selective reduction of activated CC double bonds and complements the pool of synthetic valuable enoate reductases.
- Iqbal, Naseem,Rudroff, Florian,Brigé, Ann,Van Beeumen, Jozef,Mihovilovic, Marko D.
-
experimental part
p. 7619 - 7623
(2012/09/07)
-
- Di-μ-hydroxy-bis(N,N,N′,N′-tetramethylenediamine)-copper(II) chloride [Cu(OH)·TMEDA]2Cl2: An efficient, practical catalyst for benzylation and allylation of amides
-
An efficient protocol for the benzylation or allylation of amides using the corresponding benzyl or allyl chlorides as electrophiles under basic conditions with commercially available 5 mol % of [Cu(OH)TMEDA]2Cl2 as catalyst was developed. Under these conditions, unprotected amino acids were benzylated without any racemization.
- Kumaraswamy,Pitchaiah,Ramakrishna,Ramakrishna,Sadaiah
-
p. 2013 - 2015
(2007/10/03)
-
- A practical ruthenium-catalyzed cleavage of the allyl protecting group in amides, lactams, imides, and congeners
-
A convenient methodology for the deprotection of N-allylic amide-like moieties was developed. The first examples accounting for the ruthenium-catalyzed deallylation of amides, lactams, imides, pyrazolidones, hydantoins, and oxazolidinones have been achieved by the sequential use of Grubbs carbene (isomerization step) and RuCl3 (oxidation step). A variety of substrates, including enantiopure multifunctional β- and γ-lactams, can be employed.
- Alcaide, Benito,Almendros, Pedro,Alonso, Jose M.
-
p. 2874 - 2879
(2008/02/03)
-
- Microwave-assisted N-alkylation of potassium phthalimide and potassium succinimide onto silica gel in dry media
-
Synthesis of N-alkyl phthalimides and N-alkyl succinimides through alkylation of potassium phthalimide and potassium succinimide in dry media catalyzed by phase-transfer catalyst under microwave irradiation will be reported. The reactions were with fairly high yield.
- Hekmatshoar,Heravi,Baghernejad,Asadolah
-
p. 1611 - 1614
(2007/10/03)
-
- A new highly chemoselective isomerization of allylamides
-
This work describes the first iridium-catalyzed isomerization of N-allylamides into enamides. This strategy allows the chemoselective preparation of (E)-N-(1-propenyl)-enamides and can be applied for the selective deprotection of N-allylamides.
- Neugnot, Benjamin,Cintrat, Jean-Christophe,Rousseau, Bernard
-
p. 3575 - 3579
(2007/10/03)
-
- β-, γ- and δ-Lactams as conformational constraints in ring-closing metathesis
-
The azabicycloalkenones 5, 6 and 7 were formed in excellent yields via ring-closing metathesis of the bis-alkenyl precursors 1, 2 and 3.
- Tarling, Chris A.,Holmes, Andrew B.,Markwell, Roger E.,Pearson, Neil D.
-
p. 1695 - 1701
(2007/10/03)
-
- Ring-closing olefin metathesis for the synthesis of fused nitrogen heterocycles
-
A novel technique for the efficient synthesis of fused nitrogen heterocycles containing various combinations of five- and eight-membered rings has been developed. This method features the ring-closing metathesis (RCM), which is catalyzed by the molybdenum
- Martin, Stephen F.,Chen, Hui-Ju,Courtney, Anne K.,Liao, Yusheng,Paetzel, Michael,Ramser, Melissa N.,Wagman, Allan S.
-
p. 7251 - 7264
(2007/10/03)
-
- Selective ammonolysis and aminolysis of dimethyl succinate. Synthesis of optically active N-alkylsuccinimides
-
Candida antarctica lipase catalyzes the selective monoammonolysis and aminolysis of dimethyl succinate with ammonia and aliphatic amines, respectively, in dioxane as solvent. This enzyme shows a high enantioselectivity when racemic amines are used. Optically active amidoesters are also obtained in the reaction of dimethyl succinate with racemic α-methylalkylamines in hexane as solvent. In this medium, the enzyme catalyzes the formation of N-alkylsuccinimides or optically active N-alkyl-α-methylsuccinimides from dimethyl succinate or α-methylsuccinate and amines.
- Puertas, Susana,Rebolledo, Francisca,Gotor, Vicente
-
p. 1495 - 1502
(2007/10/02)
-