Letters in Organic Chemistry - Volume 3, Issue 6, 2006

This review focuses on the use of continuous flow reactors as tools in synthetic organic chemistry and aims to highlight their many advantages, including their ability to synthesise products in high yield, purity and, where relevant, selectivity.

Reactions between tripodal CH3C(CH2NH2)3 = 'tame' and CH3C(CH2NHCH2CH2NH2)3 = 'sen' with the monomethoxycarbonylmethyl ether 1 lead to the ready isolation of tame-dicalix 2, tame-tricalix 3 and sentricalix 4. Studies of complex formation of 3 and 4 with Zn(II) showed that 'tame' residue is incapable of coordinating the metal in its N3 donor site, while Zn(II) is preferentially coordinated in the carbomethoxyamido fu Read More

Novel chiral amino-amide 9-keto-bispidines are investigated as ligands in the addition reaction of diethylzinc to aromatic aldehydes. The ligands are easily obtained by a single step procedure starting from commercially available products. Selected ligands were also supported onto different insoluble resins in order to test their activity as heterogeneous catalysts.

N-Toluenesulfonyl-L-proline amide was tested as catalyst in the enantioselective aldol addition of acetone to aromatic aldehydes in different ionic liquids. The aldolisation products were isolated in high yields (up to 98%) with enantioselectivities ranging from 50 to 90% Immobilisation of the catalyst in ionic liquids allows simple product isolation and repeated use. The chemical yields and enantioselectivities achieved were co Read More

A coating consisting of an ionic liquid (1,3-butylmethylimidazolium hexafluorophosphate [BMIM][PF6]) was deposited on silica gel as well as on a new polyvinylimidazolium phase and treated with a task specific onium salt (TSOS). The activity and stability of both immobilised Pd-species were studied and compared in Mizoroki-Heck cross coupling reactions.

Synthesis of the C3-C10 and C13-C21 segments, having seven asymmetric centers of the marine macrolide, (-)-laulimalide is reported. The requisite stereogenic centers were generated on the chirons by the application of asymmetric reactions.

We report herein an optimized practical synthesis of three novel 7-substituted eudistomin analogs (1-3). The total syntheses of these complex tetracyclic molecules were completed in 22 steps from the requisite 7-substituted indoles.

2-Deoxy ketopyranoses were prepared in very good yields and excellent stereoselectivity by a onepot procedure involving the iodohydroxylation of exo-glycals and removal of the iodide group using sodium dithionite.

Simple and efficient methods have been developed for the synthesis of orthogonally protected 2,5- diaminocyclohexanecarboxylic acid diastereomers via the stereocontrolled transformation of 2-benzyloxycarbonylamino-4-cyclohexenecarboxylic acid to its iodolactone or epoxide.

Aromatic and aliphatic Weinreb amides are selectively converted into the corresponding N-methoxy- N-methylamines by treatment with lithium aluminium hydride in the presence of aluminium chloride.

The intramolecular carbolithiation reactions of aromatic N-allyl-N-(2-lithioallyl)amines have been studied in detail. Although we have initially proposed a 6-endo ring closure for these substrates, we have found that the course of these processes starts with a 5-exo cyclization reaction. Interestingly, 3- functionalized-4-methylenepyrrolidines have been synthesized from simple starting materials.

The reaction of the partially protected (TBDMS), anti-N-Boc-3-methylamino, or anti-N-Boc-3- amino-3-phenyl-1,2-propanediols 7a or 7b, with sodium hydride, yields the oxazolidinones 8 and the silyl migration oxazinones 9, with different ratios (8a:9a; 93:7 and 8b:9b 50:50). The results, have been explained experimental and theoretically by kinetic control of the reaction.

Sulfated zirconia (ZrO2/SO4 2-) solid superacid has been proved to be an efficient reusable heterogeneous catalyst for three-component one-pot cyclocondensation reaction of β-dicarbonyl compounds and urea/thiourea with structurally diverse aromatic aldehydes in solvent-free conditions to furnish the corresponding 3,4-dihydropyrimidin-2(1H)-ones and -thiones in good to excellent yields both under microwave irradiation an Read More

We present herein a general method for the preparation of chiral terminal olefin bearing long chain α- amino acids via the following three-step sequence starting from (S)-N-Boc-2-pyrrolidone-5-carboxylic acid: (1) opening of the γ-lactam ring by an organometallic reagent, (2) keto reduction, and (3) ester hydrolysis.

Methyl 2-methoxycarbonyl-3-phenylpropionate derivatives were prepared, and their inhibitory activities for angiotensin converting enzyme (ACE) were evaluated. The inhibitiory activity of methyl 3-{4-[2- [N-(4-methylbenzylphenyl)methyl,N-methylamino]ethoxy]phenyl} -2-methoxycarbonylpropionate (5b, IC50 = 0.0039 μM) and methyl 3-{4-[2-[N-bis(4-methoxy phenyl)methyl,N-methylamino]ethoxy]phenyl Read More