Although fire is now rarely used in synthetic chemistry, it was not until Robert Bunsen invented the burner in 1855 that the energy from this heat source could be applied to a reaction vessel in a focused manner. The Bunsen burner was later superseded by the isomantle, oil bath, or hot plate as a source for applying heat to a chemical reaction. In the past few years, heating and driving chemical reactions by microwave energy has been an increasingly popular theme in the scientific community. This nonclassical heating technique is slowly moving from a laboratory curiosity to an established technique that is heavily used in both academia and industry. The efficiency of "microwave flash heating" in dramatically reducing reaction times (from days and hours to minutes and seconds) is just one of the many advantages. This Review highlights recent applications of controlled microwave heating in modern organic synthesis, and discusses some of the underlying phenomena and issues involved.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/anie.200400655

Controlled microwave heating in modern organic synthesis.

Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aube rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.

Organic Azides: An Exploding Diversity of a Unique Class of Compounds

Asymmetric 1,3-Dipolar Cycloaddition Reactions

The Diels-Alder reaction has both enabled and shaped the art and science of total synthesis over the last few decades to an extent which, arguably, has yet to be eclipsed by any other transformation in the current synthetic repertoire. With myriad applications of this magnificent pericyclic reaction, often as a crucial element in elegant and programmed cascade sequences facilitating complex molecule construction, the Diels-Alder cycloaddition has afforded numerous and unparalleled solutions to a diverse range of synthetic puzzles provided by nature in the form of natural products. In celebration of the 100th anniversary of Alder's birth, selected examples of the awesome power of the reaction he helped to discover are discussed in this review in the context of total synthesis to illustrate its overall versatility and underscore its vast potential which has yet to be fully realized.

https://www.ch.ic.ac.uk/local/organic/pericyclic/DA.pdf

The Diels--Alder reaction in total synthesis.

Introduction Cationic domino reactions Anionic domino reactions Radical domino reactions Pericyclic domino reactions Photochemically induced domino processes Transition metal catalysis Domino reactions initiated by oxidation or reduction Enzymes in domino reactions Multicomponent reactions Special techniques in domino reactions

Domino Reactions in Organic Synthesis

The September issue of Aust. J. Chem. contains a selection of papers authored by speakers at the National Congress of the Royal Australian Chemical Institute held in Adelaide, 7–12 December 2014, which integrated all areas of chemistry under one roof in the Adelaide Convention Centre. Neil Vasdev and Steven Liang (Massachusetts General Hospital and Harvard Medical School) present an account on a new avenue to synthesize radiotracers aimed at the eventual ability to radiolabel just about any substance for medicinal purposes. Rainer Koch (University of Oldenburg, Germany), H.-J. Wollweber (University of Marburg, Germany), and the present author (The University of Queensland) report on the synthesis of a-oxo oximes of isoxazolones, pyrazolones, and 1,2,3-triazolone and the elucidation of stereochemical preferences. Toshihide Horikawa (Tokushima University, Japan), Duong Do (The University of Queensland), and their colleagues describe their research on the adsorption of water and methanol on highly graphitized carbon black and activated carbon fibre. John Gladysz and co-workers (Texas A&M University) report on the syntheses of three series of trigonal bipyramidal trans-bis(phosphine) complexes, which can potentially undergo three-fold intramolecular ring closing metatheses to yield gyroscope-like complexes. Frederic Paul, Jean-Francois Halet, and their co-workers (Universite de Rennes 1, France) report a theoretical analysis of electronic structures and optical properties of a series of phenylalkynyl iron complexes, Fe(dppe)(Z-C5Me5). Unexpected hypsochromic shifts of the lower energy absorption bands upon carbon chain lengthening were observed. Bradley Smith et al. (University of Notre Dame, Indiana, USA) report enhanced squaraine rotaxane endoperoxide chemiluminescence in acidic alcohols. The squaraine rotaxane endoperoxides are storable chemiluminescent compounds that undergo a clean cycloreversion reaction, releasing singlet oxygen and emitting near-infrared light when warmed to body temperature. Acidic alcohols such as hexafluoroisopropanol greatly increase the chemiluminescence, which takes place from a squarine excited state. Interlocked rotaxanes are necessay for the effect. Philip E. Thompson (Monash Institute of Pharmaceutical Sciences) and co-workers applied click chemistry to produce linear and cyclic peptide conjugates derived from Fmocpropargyloxyprolines. The conjugates can retain the binding affinity and/or binding conformation of the parent peptide. Frances Separovic (The University of Melbourne) and her co-workers describe C-terminal modifications with hydrazide and alcohol functions that extend the antibacterial activity of a proline-rich peptide towards other Gram-negative species. Furthermore, the new analogues did not show cytotoxicity towards mammalian cells. Jianbo Wang and co-workers at Peking University, China, report Rh-catalyzed cross-coupling of diazoesters with arylstannanes as a first Stille-type coupling using diazo compounds. The reaction is operationally simple, can be carried out under mild conditions, and provides an alternative approach to the synthesis of a-aryl esters. RichardO’Hair (TheUniversity ofMelbourne) et al. report that decarboxylation takes precedence over loss of acetonitrile in silver propiolate complexes of the type [CH3C CCO2Ag2(CH3CN)n] (n1⁄4 1 or 2). Massimiliano Massi and Mark Ogden (Curtin University, Perth), Evan Moore (The University of Queensland), and coworkers have prepared a one-dimensional Eu3þ coordination polymer bearing a-nitrile-substituted b-diketonate and 1,10phenanthroline ligands, which exhibit red emission in the solid state. The sensitization process from the b-diketonate to the Eu3þ is thought to occur via an antenna effect. Aleksey Vasilev (University of Sofia, Bulgaria), Katharina Landfester (Max Planck Institute for Polymer Research, Mainz, Germany), and their co-workers report their work on assembling new two-in-onemerocyanine chromophoreswith a 1,8-naphthalimide core by using the NO2 function as a leaving group in SN-Ar reactions, thus overcoming limitations of the conventional use of halogenide leaving groups. Timothy Long et al. (Virginia Tech, USA) have synthesized a biocompatible, biodegradable, and 3D-printable polyester [poly(tri(ethylene glycol) adipate) dimethacrylate] suitable for building vascularized soft-tissue scaffolding. The polyester exhibited highly efficient photocuring, hydrolyzability, and 3D printability in a custom micro-stereolithography system. The photocured polyester film demonstrated significantly improved cell attachment and viability.

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RACI Congress Adelaide

/pdf/12th-eurasia-conference-on-chemical-sciences-2o6iwi14vk.pdf

12th Eurasia Conference on Chemical Sciences

The title compound, C20H16O3, is a representative of a class of substituted α-pyrones with a distorted pyran ring.

2-Benzyl-1-hydroxy-5,6-dihydro-3H-naphtho(2,1-b)pyran-3-one

The 7th Heron Island Conference on Reactive Intermediates and Unusual Molecules – Synthesis and Mechanism was held from July 9-15, 2016 at the Heron Island Resort on the Great Barrier Reef, Brisbane, Australia. About 80 scientists from around the globe attended the meeting to present their work in either oral or poster format. The event was attended by a number of representatives from different sections of concerned research areas. The event provided unique opportunities for Australian and overseas chemists to interact on subject areas varying across physical, spectroscopic, and mechanistic chemistry, organic synthesis, theoretical and computational chemistry, materials chemistry, biological and medicinal chemistry, and inorganic chemistry.

/pdf/7th-heron-island-conference-on-reactive-intermediates-and-2in6gdpcx3.pdf

7th Heron Island Conference on Reactive Intermediates and Unusual Molecules

Stable 1H-1,3-diazepines 7–9,10,13,14,17 and 19 are obtained, often in high yields, by photolysis of triflouoromethyl-substituted azido- or tetrazolo-pyridines in the presence of alcohols or amines; in some cases 5H-1,3-diazepines are also formed(11,21 and 23).

Curt Wentrup

Papers

RACI Congress Adelaide

12th Eurasia Conference on Chemical Sciences

2-Benzyl-1-hydroxy-5,6-dihydro-3H-naphtho(2,1-b)pyran-3-one

7th Heron Island Conference on Reactive Intermediates and Unusual Molecules

Synthesis of 1H‐ and 5H‐1,3‐Diazepines from Azido‐ and Tetrazolo‐ Pyridines.