Signaling Recognition Events with Fluorescent Sensors and Switches.

Efficient synthetic methods required to assemble complex molecular arrays include reactions that are both selective (chemo-, regio-, diastereo-, and enantio-) and economical in atom count (maximum number of atoms of reactants appearing in the products). Methods that involve simply combining two or more building blocks with any other reactant needed only catalytically constitute the highest degree of atom economy. Transition metal-catalyzed methods that are both selective and economical for formation of cyclic structures, of great interest for biological purposes, represent an important starting point for this long-term goal. The limited availability of raw materials, combined with environmental concerns, require the highlighting of these goals.

http://science.sciencemag.org/content/sci/254/5037/1471.full.pdf

The atom economy--a search for synthetic efficiency

The biaryl structural motif is a predominant feature in many pharmaceutically relevant and biologically active compounds. As a result, for over a century 1 organic chemists have sought to develop new and more efficient aryl -aryl bond-forming methods. Although there exist a variety of routes for the construction of aryl -aryl bonds, arguably the most common method is through the use of transition-metalmediated reactions. 2-4 While earlier reports focused on the use of stoichiometric quantities of a transition metal to carry out the desired transformation, modern methods of transitionmetal-catalyzed aryl -aryl coupling have focused on the development of high-yielding reactions achieved with excellent selectivity and high functional group tolerance under mild reaction conditions. Typically, these reactions involve either the coupling of an aryl halide or pseudohalide with an organometallic reagent (Scheme 1), or the homocoupling of two aryl halides or two organometallic reagents. Although a number of improvements have developed the former process into an industrially very useful and attractive method for the construction of aryl -aryl bonds, the need still exists for more efficient routes whereby the same outcome is accomplished, but with reduced waste and in fewer steps. In particular, the obligation to use coupling partners that are both activated is wasteful since it necessitates the installation and then subsequent disposal of stoichiometric activating agents. Furthermore, preparation of preactivated aryl substrates often requires several steps, which in itself can be a time-consuming and economically inefficient process.

http://aether.cmi.ua.ac.be/artikels/Artikels%20Gitte/Artikels/Reviews/Heck-Type-lautens.pdf

Aryl-aryl bond formation by transition-metal-catalyzed direct arylation.

The direct functionalization of C-H bonds in organic compounds has recently emerged as a powerful and ideal method for the formation of carbon-carbon and carbon-heteroatom bonds. This Review provides an overview of C-H bond functionalization strategies for the rapid synthesis of biologically active compounds such as natural products and pharmaceutical targets.

C-H bond functionalization: emerging synthetic tools for natural products and pharmaceuticals

The 3,3'-pyrrolidinyl-spirooxindole unit is a privileged heterocyclic motif that forms the core of a large family of alkaloid natural products with strong bioactivity profiles and interesting structural properties. Significant recent advances in the synthesis of this fused heterocyclic system have led to intense interest in the development of related compounds as potential medicinal agents or biological probes.

Pyrrolidinyl-spirooxindole natural products as inspirations for the development of potential therapeutic agents.

Primary and secondary alcohols effect alkylation of primary and secondary amines in the presence of rhodium, iridium, and ruthenium compounds at ⩽ 100 °C, whereby selective monoalkylation of primary amines can be achieved and heterocyclic rings can be constructed by both inter- and intra-molecular processes.

Transition metal-catalysed N-alkylation of amines by alcohols

The synthesis of fused ring nitrogen heterocycles via regiospecific intramolecular heck reactions

X-Y-ZH Systems as potential 1,3-dipoles : Part 15. Amine generated azaallyl anios versus metallo-1,3-dipoles in cycloadditions of α-amino acid esters. Facile regio- and stereo-specific formation of pyrrolidines

Oxidation of alcohols by transition metal complexes part V. Selective catalytic monoalkylation of arylacetonitriles by alcohols

The use of a new amino acid reagent 1,8-diazafluoren-9-one (DFO), which produces a highly fluorescent species with latent fingerprints on paper, is described. Spectral characteristics of the fluorescent fingerprint show excitation (λex approximately 470 nm) and emission (λex approximately 570 nm) maxima in the visible part of the spectrum. Some printing inks fluoresce under these conditions and would therefore hinder fingerprint detection, but optical brighteners present in paper do not interfere. Fluorescent fingerprints visualized by DFO revealed more fingerprint detail than ninhydrin, the standard method for such surfaces.

Ronald Grigg

Papers

Transition metal-catalysed N-alkylation of amines by alcohols

The synthesis of fused ring nitrogen heterocycles via regiospecific intramolecular heck reactions

X-Y-ZH Systems as potential 1,3-dipoles : Part 15. Amine generated azaallyl anios versus metallo-1,3-dipoles in cycloadditions of α-amino acid esters. Facile regio- and stereo-specific formation of pyrrolidines

Oxidation of alcohols by transition metal complexes part V. Selective catalytic monoalkylation of arylacetonitriles by alcohols

The Use of 1,8-Diazafluoren-9-one (DFO) for the Fluorescent Detection of Latent Fingerprints on Paper. A Preliminary Evaluation