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The synthesis of azobenzene derivatives and of azo-linked carbohydrate moieties is reviewed. The report contains 119 references. Figure options Download full-size image Download as PowerPoint slide

The microwave-assisted intramolecular [3 + 2] cycloaddition reaction of azomethine ylides to activated and nonactivated alkenes and alkynes is described. The procedure allows the synthesis of pyrrolidines and pyrrole products in good to excellent overall yields in short reaction times. It appears from parallel comparative studies that the microwave procedure favors the reaction times and overall purity of the crude reaction mixture. The reactions can also be performed in the absence of solvent. [reaction: see text]

The reaction between Grignard reagents prepared from allylic or propargylic halides and the N-phenylsulfenimine derived from the heptane-2,6-dione affords primary 1-alkenyl (or alkynyl)-3-methylcyclohex-2-enamines in good yields.

Reaction of N-unsubstituted ketimines with organoaluminum reagents prepared from allylic and propargylic halides, allows to prepare, in good yields, tertiary carbinamines with three different groups (phenyl, alkyl and α-unsaturated group) on the tertiary carbon center.

A new general synthesis of C-subtituted α -aminoacids is described, using at first the regioselective reaction between α -unsaturated organozincs and N -(phenylsulfanyl)iminoesters.

Reaction of N-unsubstituted ketimines with organoaluminum reagents prepared from allylic and propargylic halides, allows to prepare, in good yields, tertiary carbinamines with three different groups (phenyl, alkyl and α-unsaturated group) on the tertiary carbon center.

The reaction between Grignard reagents prepared from allylic or propargylic halides and the N-phenylsulfenimine derived from the heptane-2,6-dione affords primary 1-alkenyl (or alkynyl)-3-methylcyclohex-2-enamines in good yields.

The synthesis of azobenzene derivatives and of azo-linked carbohydrate moieties is reviewed. The report contains 119 references. Figure options Download full-size image Download as PowerPoint slide

Organometallics (CH3)2CCCHM (M  MgBr, Al 2 3 Br, ZnBr) are easily prepared from the tertiary bromide (CH3)2C(Br)CCH. They often react to give only acetylenic products but, with some reagents, a mixture of acetylenic and allenic compounds is obtained.

Reactions of α-ethylenic mesitylketones with a series of organometallic compounds including allylic organometallics and organolithium compounds proceed via exclusive conjugated additions as a result of the steric congestion of the carbonyl of these ketones.

The straightforward synthesis of families of novel tri-cyclic and tetracyclic pyrrolino and indolino heterocycles in a one-pot [3+2]-cycloaddition reaction is described. The process enables the synthesis of diversified pyrroles or pyrrolines in high yields in a single step. Microwave and conventional thermal conditions were explored, with remarkable acceleration observed under the microwave conditions.

(R = H) [10160-87-9] C7H12O2 (MW 128.17) InChI = 1S/C7H12O2/c1-4-7(8-5-2)9-6-3/h1,7H,5-6H2,2-3H3 InChIKey = RGUXEWWHSQGVRZ-UHFFFAOYSA-N (R = Li) [51756-42-4] C7H11LiO2 (MW 134.10) InChI = 1S/C7H11O2.Li/c1-4-7(8-5-2)9-6-3;/h7H,5-6H2,2-3H3; InChIKey = IKXQCHGDSMYFJO-UHFFFAOYSA-N (intermediate for the synthesis of unsaturated and polyunsaturated compounds and numerous heterocycles1) Alternate Names: propiolaldehyde diethyl acetal; propargylaldehyde diethyl acetal. Physical Data: bp 138–139.5 °C; d 0.894 g cm−3. Solubility: sol standard organic solvents. Form Supplied in: colorless liquid; commercially available. Analysis of Reagent Purity: IR: 3260, 2125 cm−1; 1H NMR (CDCl3): δ 1.24 (t, J = 7, 6H), 2.58 (d, J = 2, 1H), 3.71 (q of d, J = 7, 2, 4H), 5.21 (d, J = 2, 1H). Preparative Method: the synthesis of this reagent can be accomplished according to eq 1. The dehydrobromination step can be carried out with Potassium Hydroxide in ethanol,2 with Sodium Amide in liquid ammonia,3 or by using Sodium Hydroxide in the presence of a phase transfer agent.1a,4 3,3-Diethoxy-1-propyne can also be prepared according to eq 2.5 (1) (2) The lithio derivative, named (3,3-diethoxy-1-propynyl)lithium, is easily prepared by reaction of 1 equiv of a saturated lithium compound (e.g. n-Butyllithium) with a solution of the acetal in ether or THF.6 Purification: by distillation at reduced pressure, bp 95–96 °C/170 mmHg.1a Handling, Storage, and Precautions: should be stored in a refrigerator and protected from moisture.

The cleavage of the specific vinyl ether linkage at the sn-1 position of plasmalogens leads to the formation of two products: the 1-lyso-2-acyl glycerophospholipid and a long-chain fatty aldehyde. Plasmalogens are measured by quantifying one of these two products. In this paper, we describe a rapid and sensitive procedure for measuring plasmalogens via quantification of long-chain fatty aldehydes. After lipid extraction, the sn-1 vinyl ether bond of plasmalogens is cleaved by acidic hydrolysis. The produced aldehydes are then derivatized with (pentafluorobenzyl)hydroxylamine hydrochloride and analyzed by gas chromatography/mass spectrometry in selected-ion mode. Plasmalogens are then indirectly quantified by subtracting the free aldehydes obtained without prior HCl treatment from the total aldehydes obtained after acidic hydrolysis. This method is applied to three rat brain areas selected for this study. Two of these are affected in neurodegenerative diseases (cerebral cortex and hippocampus) and one is rich in white matter (cerebellum). In comparison to other procedures, the advantages of this method are not only its usefulness in plasmalogen quantification but also the identification of aldehydic breakdown products.

Corrigendum to ‘‘Azobenzenesdsynthesis and carbohydrate applications’’ [Tetrahedron 65 (49) (2008) 10105–10123] Florian Hamon , Florence Djedaini-Pilard , Francis Barbot , Christophe Len a,c,* Universite de Poitiers, Synthese et Reactivite des Substances Naturelles, UMR CNRS 6514, 40 Avenue du Recteur Pineau, F-86022 Poitiers Cedex, France Universite de Picardie Jules Verne, Laboratoire des Glucides, UMR CNRS 6219, 33 rue Saint Leu, F-80039 Amiens, France Universite de Technologie de Compie‘gne, Transformations Integrees de la Matie‘re Renouvelable, EA 4297 UTC/ESCOM, 1 allee du reseau Jean-Marie Buckmaster, F-60200 Compie‘gne, France

Lithium organocuprates, R 2 CuLi, react with the ketone CH 3 COCHCHCH CHCH 3 to give the β-ethylenic ketones CH 3 COCH 2 CHCHCH(R)CH 3 corresponding to an 1–6 addition reaction.

The reaction of saturated lithium organocuprates with the trienic ketone CH3(CHCH)3COCH3 and with the trienic ester CH3 (CHCH)3COOC2H5 proceeds by a 1,8 conjugate addition to give a β,δ-diethylenic carboynl compound.

Synthesis of 2-alkylaminoethanethiols with a tertiary group fixed to the nitrogen atom has been achieved. A very convenient method of access to such 2-alkylaminoethanethiols with one, two, and three allyl substituents is the reaction between allylic organomagnesium compounds and thiazolidines, 2-alkylthiazolines, and 2-methylthiothiazolines respectively.

Contrary to a recent report, it is shown that allylic Grignard reagents prepared by treating allylic Grignard reagents with isoprene and a catalytic amount of Cp2TiCl2 react normally with carbon dioxide and carbonyl compounds: a complete allylic rearrangement is observed.

Under suitable conditions, the reaction of allylzinc bromide with a carbonyl compound can be reversible.

The reaction of thiazolines with allylic Grignard reagents provides a very convenient route to 2-(2-alkenyl)thiazolidines. The applicability of this method has been established.

The reaction between an organometallic compound RM and the mixed orthoester (C6H5O)2CHOC2H5 gives either a mixed acetal RCH(OC2H5)OC6H5 or an ether R2CHOC2H5, depending on the structure of the organometallic compound used.

α-Unsaturated organoaluminium compounds react easily in ether with acetals and ketals to give the β-unsaturated ethers corresponding to the substitution of one alkoxy group.

Organoaluminium compounds prepared in ether from RCCCH 2 Br react with acetals to give solely α-allenic ethers.

A new way to vinylic ethers from acetals Acetals react at low temperatures in presence of a Lewis acid (aluminium chloride or magnesium bromide) with tertiary amine to give in good yields the vinylic ethers corresponding to the elimination of one molecule of alcohol.

Organometallics readily add to the double bond of 1-(functionally substituted alkene phosphonates to give highly substituted phosphonates.

When they react with N,N-diethylsorbamide, saturated and allylic Grignard reagents give γ,δ-ethylenic amides (1,4-addition) whereas saturated and allylic lithium organocuprates give β,γ-ethylenic amides (1,6-addition).

Resume Allylic organometallics react with N-tosyl iminoethers and N-tosyl iminocarbonates to produce sulfonamides which give the title amino compounds by reaction with sodium in liquid ammonia.