Tin Mediated Allylation of Aldimines with Allyl Bromide

SyntheticinterestsinhighlyfunctionalizedacyclicandcyclicamineshavecontributedtothewealthofexPerimentalmethodologydeveloPedfortheadditionofcarbanionstothecarbon-nitrogendoublebondofimines.Generally,organometallicreagentsorilltermedi-atesareusedascarbanionsandadditionofallylicorganometallicspeciestothenieconshtutesavaluablemethodforthesynthesisofhomoallylamines.'Amongthese,allyLlithium,'-magnesium,'-zinc,'-boraneandboronate,'-silaneand-stannane'havebeenusedforallylationofdriines.Ontheotherhand,…     

Asymmetric Mannich-Type Reactions of Aldimines with a Chiral Acetate

We introduce here a strategy that enables effective addition of lithium enolates of acetates to aldimines. The new method depends strongly on the use of o-alkoxy (or o-fluoro) aniline-derived aldimines which have been found to have a potential effect on the enolate addition. This scope was expanded to the asymmetric process using the chiral acetate. A Lewis acid additive has a complementary role in the pronounced activation of imine functionalities.     

纯水中金属钕诱发芳香醛烯丙基化反应的研究

在Nd-SnCl₂-H₂O体系中, 用烯丙基溴超声诱发下进行了一系列芳香醛的烯丙基反应, 室温反应50～60 min得76%～93%烯丙基化产物; 而不用超声波时同样体系中搅拌3～4 h高烯丙基醇产率为30%～86%. 该方法时间短、产率高、环境友好.     

水溶液中金属铅诱发芳香醛的烯丙基化反应

超声辐射下,在Pb-THF-NH4C1-H2O体系中,烯丙基溴与一系列芳香醛室温反应4h,得62%～98%烯丙基化产物;而同样体系中搅拌20h,高烯丙基醇产率为63%～97%.     

Indium and Tin Mediated Allylation Reactions of 3-Hydroxycephem in Aqueous Media

Allylation of the C-3 position of the cephem nucleus was accomplished by either indium mediated or indium trichloride promoted tin mediated allylation reactions in aqueous media. Both methods gave 3-allyl-3-hydroxycephams 2a - 2d, in moderate to excellent yields.     

Studies on the Allylation Reactions of Aldehydes and Ketones with Lanthanum in Water

The allylation reactions of aldehydes and ketones were carried out in 25%–98% (or 29%–96%) yield with La/SnCl₂/H₂O under ultrasound irradiation (or stirring) at rt for 1 h (or 4 h). The main advantage of the present procedure is the higher yield and the environmentally benign method.     

超声辐射下水相介质中金属锡引发芳香醛酮的烯丙基化反应

超声波作用下, Sn/H₂O体系中, 芳香醛酮在室温下进行烯丙基化反应, 45 min内得到60%～98%的烯丙基化产物.     

Aldimines of Cardenolides and Cardenolide-Glycosides

New aldimines were synthesized from the cardenolide strophantidin and cardenolide-glycosides erysimin and cymarin and included morpholine, nitrile, pyridine, furan, hydroxy- and methoxyphenyl, piperidine, and other derivatives. An effective modified method for synthesizing aldimines was proposed. 52 new compounds were synthesized. Their structures were confirmed by IR and PMR spectra and elemental analysis.__________Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 268–271, May–June, 2005.     

Asymmetric Petasis Borono‐Mannich Allylation Reactions Catalyzed by Chiral Biphenols

Chiral biphenols catalyze the asymmetric Petasis borono‐Mannich allylation of aldehydes and amines through the use of a bench‐stable allyldioxaborolane. The reaction proceeds via a two‐step, one‐pot process and requires 2–8 mole % of 3,3′‐Ph₂‐BINOL as the optimal catalyst. Under microwave heating the reaction affords chiral homoallylic amines in excellent yields (up to 99 %) and high enantioselectivies (er up to 99:1). The catalytic reaction is a true multicomponent condensation reaction whereas both the aldehyde and the amine can possess a wide range of structural and electronic properties. Use of crotyldioxaborolane in the reaction results in stereodivergent products with anti‐ and syn‐diastereomers both in good diastereoselectivities and enantioselectivities from the corresponding E‐ and Z‐borolane stereoisomers.     

Allylation Reactions of Aromatic Aldehydes with Antimony in Aqueous Media Under Ultrasonic Irradiation

The allylation reactions of aromatic aldehydes with allyl bromide were carried out in 89–98% yield with Sb-H₂O-KF-CH₃OH under ultrasound irradiation at rt for 2.5 h. The reactions in the same system gave allylic alcohols in 30–69% yield with stirring for 24 h. The main advantages of the present procedure are shorter reaction time, better yield, and environmental friendliness.     

Solid-Liquid Phase Transfer Catalytic Synthesis (V) Michael Addition,Carbonyl Addition Reactions of the Aldimines

Nucleophilic addition of aldimines to the active methylene compounds and aldehyde compounds can be performed in solidliquid PTC conditions. The reactions are synthetically useful in preparing α-amino acids.     

Synthesis and Aminoalkylation of N-Propargyl Triterpene Aldimines

Russian Journal of Organic Chemistry - Mannich reaction of N-propargyl triterpene aldimines obtained from betulonic and oleanonic aldehydes gave new aminoalkyl derivatives containing an...     

Fe‐Catalyzed Multicomponent Reactions: The Regioselective Alkoxy Allylation of Activated Olefins and its Application in Sequential Fe Catalysis

We present herein a versatile and broadly applicable Fe‐catalyzed regioselective alkoxy allylation of activated double bonds. Substituted allylic carbonates are converted into the corresponding σ‐enyl Fe complexes by reaction with Bu₄N[Fe(CO)₃(NO)] (TBAFe) at 30 °C. The liberated alkoxide adds to an activated double bond with the generation of a C‐nucleophile, which is trapped by the σ‐enyl Fe complex in a regioselective manner. Alternatively, the alkoxide acts as a base in deprotonating an external pronucleophile, which undergoes Michael addition. The method is characterized by a broad functional group tolerance, mild reaction conditions, low catalyst loadings, and high regioselectivities in favor of the ipso‐substitution product.     

Solvent-Free Addition Reaction of Allylzinc Bromide and Aldimines

Barbier-type allylation of aldimines with allylzinc bromide took place rapidly under solvent-free conditions. The procedure is environmentally benign and operationally simple, has good regioselectivity, and gives good to excellent yields.     

The Crystal and Molecular Structures of Pb(II) Complexes with Furan-2-Carboxylate and Furan-3-Carboxylate Ligands

The crystals of Pb(II) 2-furancarboxylate (title compound I) contain tetrameric structural units Pb₄(2-FCA)₈(H₂O₂) in which four Pb(II) ions are bridged by carboxylate oxygen atoms forming a circular moiety. In addition, pairs of Pb(II) ions are bridged by carboxylate oxygen atoms inside this moiety. The molecular pattern observed in Pb(II) 3-furancarboxylate (title compound II) is polymeric. It consists of Pb(3-FCA)₂(H₂O) structural units bridged by carboxylate oxygen atoms donated by the furan-3-carboxylate (3-FCA) ligands which are bidentate, using both their carboxylate oxygen atoms for chelation. The coordination around Pb(II) ions is eightfold and ninefold including, apart from carboxylate oxygen atoms, a water oxygen atom and oxygen atoms donated by the furan rings of the ligand molecules. Hydrogen bonds with the water molecule as the donor operate between adjacent ligand molecules. The stereochemical activity of the lone 6s ² electron pair on the Pb(II) is observed in title compound II.     

Zinc-Mediated Addition of Bromoacetonitrile to Aldimines

Thecarbon-nitrogendoubleb0ndhaselectrophilicityandtlleadditi0nofcarbonnucle0-plillestocarbon-nitf0gendoublebondinilninesconstitutesanimpohalltmeti1odforti1eprepamtionofsecondnyamines.Asaclleapai1defficientreagentmetalliczinchasbeenwidelyusedinil1eallylationofaldehydesandket0nes',aswellasilnines2.Itissh0wnll1atzinclinsalilghreactivitytomediatehleforlnation0fcarbon-carbonbondundermildreachoncondihons,anditwouldhaVeawiderusein0rganicSynti1esis.BecauseofitselectronwitlldrawiIlgproperty,llleCNgro…