Theoretical studies of 31P NMR spectral properties of phosphanes and related compounds in solution

Selected theoretical methods, basis sets and solvation models have been tested in their ability to predict 31P NMR chemical shifts of large phosphorous-containing molecular systems in solution. The most efficient strategy was found to involve NMR shift calculations at the GIAO-MPW1K/6-311++G(2d,2p)//MPW1K/6-31G(d) level in combination with a dual solvation model including the explicit consideration of single solvent molecules and a continuum (PCM) solvation model. For larger systems it has also been established that reliable 31P shift predictions require Boltzmann averaging over all accessible conformations in solution

Activation of Pyridinium Salts for Electrophilic Acylation: a Method for Conversion of Pyridines into 3-Acylpyridines

Cyanide adducts of N-MOM pyridinium salts react with strong acylating reagents to provide 3-acyl-4-cyano-1,4-dihydropyridines that can be aromatized to 3-acylpyridines using ZnCl 2 in refluxing ethanol.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41517/1/10593_2004_Article_496956.pd

RECENT CASES

Hydride abstraction from monocationic hydride bridged salts [H­(H₂B–L)₂]⁺ [B­(C₆F₅)₄]¯ (L = Lewis base) generates an observable primary borenium cation for L = <i>i</i>Pr_<i>2</i>NEt, but with L = Me₃N, Me₂NPr, or several <i>N</i>-heterocyclic carbenes, highly reactive dicationic dimers are formed

Development of a Mild and Versatile Directed Cycloaddition Approach to Pyridines

The aza-Diels–Alder cycloaddition of 1,2,4-triazines with alkynes offers a rapid and convenient method for the synthesis of highly substituted pyridines, but often requires harsh conditions and long reaction times. The present study offers a solution to these limitations by use of a temporary tether established by a Lewis acid–base complexation of in situ generated alkynylboranes and triazines bearing a Lewis basic donor. The cycloaddition reactions take place within 20 min at 40 °C and provide direct access to a broad range of pyridines with complete and predictable regiocontrol. The carbon[BOND]boron bond can be further functionalised by cross-coupling allowing further functionality to be introduced after cycloaddition

4-Chloro-N-methyl-2-(1,2,3,4-tetra­hydro­isoquinolin-1-yl)aniline

The racemic title compound, C16H17ClN2, shows a tetra­hydro­isoquinoline skeleton with a 4-chloro-N-methyl­aniline group linked to the C atom at position 1. The dihedral angle between the benzene rings is 85.82 (4)°. An intra­molecular N—H⋯N hydrogen bond occurs. In the crystal, mol­ecules are linked through inter­molecular C—H⋯π inter­actions

Investigations into the effectiveness of deuterium as a "protecting group" for C-H bonds in radical reactions involving hydrogen atom transfer.

addresses: School of Biosciences (originally Department of Chemistry), University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK. [email protected]: Journal Article; Research Support, Non-U.S. Gov'tCopyright © 2008 Royal Society of ChemistryCompetition experiments have been carried out to determine the extent to which deuterium can be used as a protecting group for carbon-hydrogen bonds in radical-based intramolecular hydrogen atom transfer processes

Highly diastereoselective synthesis of substituted pyrrolidines using a sequence of azomethine ylide cycloaddition and nucleophilic cyclization

Abstract: Although cycloadditions of azomethine ylides usually give mixtures of endo/exo adducts, we successfully tuned the mechanistic path of a new reaction cascade to afford substituted pyrrolidines in high yields and diastereomeric purity. This was achieved by forcing the demetalation of tin- or silicon-substituted iminium ions, followed by azomethine ylide cycloaddition and nucleophilic cyclization. Structural complexity is thus built rapidly in a fully controlled one-pot reaction cascade

Copper(II)-mediated synthesis of indolequinones from bromoquinones and enamines

The reaction of enamines and bromoquinones in the presence of copper(II) acetate and potassium carbonate results in a regiospecific synthesis of indolequinones. The reaction is broad in scope and scalable and provides a route to the core structure that is present in several biologically interesting natural and synthetic compounds