SNP detection using trityl mass tags.

A new method suitable for single nucleotide polymorphism (SNP) detection using differential oligonucleotide probe extension has been developed. Sulfur-linked laser-cleavable trityl labels are implemented in this protocol. The method is based on mass spectrometry and utilizes a single surface for affinity purification of extended probes and matrix-independent desorption-ionization of the cleavable labels.

Reactive trityl derivatives: stabilised carbocation mass-tags for life sciences applications.

The rational design of novel triarylmethyl (trityl)-based mass tags (MT) for mass-spectrometric (MS) applications is described. We propose a "pK(R+) rule" to correlate the stability of trityl carbocations with their MS performance: trityls with higher pK(R+) values ionise and desorb better. Trityl blocks were synthesised that have high pK(R+) values and are stable in conditions of MS analysis; these MTs can be ionised by matrix as well as irradiation with a 337 nm nitrogen laser.

Novel mass tags for single nucleotide polymorphism detection.

A new method suitable for single nucleotide polymorphism detection and other applications based on oligonucleotide probe extension has been developed. The method is based on mass spectrometry and utilizes a single surface for affinity purification of extended probes and matrix-independent desorption/ionization of the cleavable labels. A new family of sulfur-linked laser-cleavable trityl labels with vastly improved flying abilities is implemented in this study.

Synthesis of enantiopure (alphaS,betaS)- or (alphaR,betaS)-beta-amino alcohols by complete regioselective opening of aminoepoxides by organolithium reagents LiAlH4 or LiAlD4.

The reaction of chiral (2R,1'S)- or (2S,1'S)-2-(1-aminoalkyl)epoxides, 1 or 2 with a variety of organolithium compounds to obtain the corresponding (alphaS,betaS)- or (alphaR,betaS)- beta-amino alcohols in enantiopure form is reported. In both cases, the opening of the oxirane ring at C-3 proceeded with total regioselectivity. Moreover, the ring opening of aminoepoxides 1 or 2 by hydride (utilizing LiAlH4) to obtain the corresponding (2S,3S)- or (2R,3S)-3-aminoalkan-2-ols is also described.

Selective ring-opening of nonactivated amino aziridines by thiols and unusual nucleophilic substitution of a dibenzylamino group.

[Reaction: see text]. The reaction of chiral 2-(1-aminoalkyl)aziridines 1 with different thiols, in the presence of BF3*Et2O, is reported. The obtained products were dependent on the structure of the starting amino aziridines 1.

S(O)-pixyl protecting group as efficient mass-tag.

We report herein the design, preparation and first applications of novel trityl tags with adjustable stability, efficient as protecting groups or MS analytes.

Stereoselective functionalization of 2-(1-aminoalkyl)aziridines via lithiation of aziridine-borane complexes.

Highly selective functionalization of the aziridine ring of (2S,1'S)-2-(1'-aminoalkyl)aziridines 1, through successive formation of aziridine-borane complexes, lithiation, treatment with a variety of electrophiles and final decomplexation is described. The influence of the structure of the starting complexes 2 and of the electrophiles in the stereoselectivity of this process has been studied. Finally, successive double lithiation-electrophile reactions were carried out affording enantiopure 1,2,3,3-tetrasubstituted aziridine-borane complexes with high selectivity.

Synthesis of (E)-alpha-hydroxy-beta,gamma-unsaturated amides with high selectivity from alpha,beta-epoxyamides by using catalytic samarium diiodide or triiodide.

The highly stereoselective synthesis of (E)-alpha-hydroxy-beta,gamma-unsaturated amides starting from alpha,beta-epoxyamides, by using catalytic SmI2 or SmI3, was achieved. This transformation can also be carried out by using SmI2 generated in situ from samarium powder and diiodomethane. The starting compounds 1 are easily prepared by the reaction of enolates derived from alpha-chloroamides with ketones at -78 degrees C.

Addition reaction of vinylic reagents, derived from alpha-chloroenones, to carbonyl compounds promoted by samarium diiodide.

A new samarium diiodide-promoted addition reaction of vinylsamarium reagents, derived from (Z)-alpha-chloro-alpha,beta-unsaturated phenones 1, to both ketones (in THF) and aldehydes (in acetonitrile) led to (Z)-2-(1-hydroxyalkyl)-2,3-unsaturated ketones in good yield. These transformations took place with total or very high inversion of the stereochemistry of the C-C double bond of the starting chloroenone, producing the Z diastereoisomer. A new methodology to prepare SmI(2) in acetonitrile by sonic treatment of 1,2-diiodoethane with Sm powder is also described.

Synthesis of different chiral amino gamma-butyrolactones and amino gamma-butenolides.

Different transformations of chiral epoxy esters 1 afford two different amino gamma-butyrolactones 2 and 6, and amino gamma-butenolides 8, by different nucleophilic opening-closing processes. [reaction: see text]

Stereoselective synthesis of functionalized gamma-amino esters: azetidinium salts and epoxy esters.

Addition of several lithium ester enolates to chiral 1-aminoalkyl chloromethyl ketones 1 affords enantiomerically pure 3-hydroxyazetidinium salts 3 or 3-(1'-aminoalkyl)-3,4-epoxy esters 4, depending on the reaction conditions. [reaction: see text]

Synthesis of Isotopically Labeled (E)-β,γ-Unsaturated Esters with Total or High Diastereoselectivity by Using Samarium Diiodide.

A simple, efficient, highly diastereoselective method for preparing (E)-α,δ-dideuterio-β,γ-unsaturated esters: SmI -promoted reduction/elimination of α-halo-β-hydroxy-γ,δ-unsaturated esters in the presence of D O. This provides the desired products in which the C-C double bond is generated with total or high diastereoselectivity.