Alistair Boyer

University of Glasgow | UofG · School of Chemistry

Petromyroxol is a nonracemic mixture of enantiomeric oxylipids isolated from water conditioned with larval sea lamprey. The (+)-antipode exhibits interesting biological properties, but only 1 mg was isolated from >100 000 L of water. Recently, transition-metal-catalyzed denitrogenation of 1-sulfonyl-1,2,3-triazoles has emerged as a powerful strateg...

Rhodium(II) acetate catalyzes the denitrogenative transformation of 4-substituted 1-sulfonyl-1,2,3-triazoles with pendent allyl and propargyl ethers and thioethers to onium ylides that undergo [2,3]-sigmatropic rearrangement to give 2-tetrasubstituted heterocycles with high yield and diastereoselectivity.

Rhodium(II) acetate catalyzes the denitrogenative transformation of 5-substituted and 4,5-disubstituted 1-sulfonyl-1,2,3-triazoles with pendent allyl and propargyl ether motifs to oxonium ylides that undergo [2,3]-sigmatropic rearrangement to give substituted dihydrofuran-3-imines in high yield and diastereoselectivity.

Chloroacetic acid promotes an efficient and diastereoselective intramolecular cascade reaction of electron-deficient ynenones to deliver products featuring a 2,3,5-trisubstituted furan bearing a fused cyclopropyl substituent at the 5-position. Synthetically relevant polycyclic building blocks featuring rings of various sizes and heteroatoms have be...

Top cat! Tetrahydrothiophene is an efficient organocatalyst for the synthesis of highly substituted furfuryl products from readily accessible electron-poor enynes under neutral reaction conditions. This process is applicable to a wide range of nucleophiles and enynes and can be used in a domino organocatalysis sequence.

The asymmetric transformation of substituted oxabicyclic alkenes into bicyclo[2.2.2]lactones is reported.

Catalyst-controlled asymmetric ring opening of a racemic oxabicyclic alkene leads to two readily separable regioisomeric products both in excellent ee. A cationic Rh catalyst, with added NH(4)BF(4) to modulate reactivity, was required to obtain synthetically useful yields. The utility of each substituted aminotetralin product has been demonstrated...

Rhodium(I) catalysts promote the transformation of o-alkynyl phenols and anilines to the corresponding benzo[b]furans and indoles. The reaction is postulated to proceed via a transient 3-rhodium heterocycle intermediate, which can be trapped with suitable electrophiles to give poly-substituted heterocycles. In the case of mono-substituted electron-...

The insect antifeedant azadirachtin (1) is a structurally complex compound derived from the Indian neem tree, Azadirachta indica. Since its isolation in 1968, the tremendous efforts devoted to its total synthesis have been frustratingly unsuccessful. However, in this account Ley and coworkers reveal a degradative approach to the synthesis of azadir...

A second bite of the apple: A new and highly efficient synthesis of the propargylic mesylate fragment of azadirachtin has been accomplished (see scheme; Bn = benzyl, Ms = methanesulfonyl, PMB = para-methoxybenzyl, TBDPS = tert-butyldiphenylsilyl). An enantioselective catalytic hetero Diels-Alder reaction sets up the stereocenter at C15, which then...

Das Azadirachtin war Gegenstand intensiver Forschungen, seit es 1968 erstmals aus dem Niembaum isoliert wurde. Über 1000 Publikationen gibt es mittlerweile, die die strukturellen, biologischen und synthetischen Aspekte dieses Naturstoffs in allen Facetten beschreiben. In diesem Aufsatz geben wir einen Überblick über die langjährigen, weltweiten Bem...

We describe in full the first synthesis of the potent insect antifeedant azadirachtin through a highly convergent approach. An O-alkylation reaction is used to unite decalin ketone and propargylic mesylate fragments, after which a Claisen rearrangement constructs the central C8-C14 bond in a stereoselective fashion. The allene which results from th...

The synthesis of a family of O-silylcarbamates from the corresponding silylamines has been achieved simply by heating the silylamine in supercritical carbon dioxide (scCO2), and these O-silylcarbamates have been shown to be effective precursors for the synthesis of a range of symmetrical and unsymmetrical ureas.

The synthesis of five natural products (3, 6, 7, 10, and 14), isolated from the Indian neem tree Azadirachta indica, is reported from a common intermediate (2). The judicious choice of transacetalization conditions allows efficient access to both the azadirachtinin (9 and 10) and the azadirachtin (3, 6, 7, and 14) skeletons.

Azadirachtin has been the subject of intensive research within the scientific community ever since its isolation from the neem tree in 1968. There are now over 1000 publications relating to this natural product which cover all aspects of structural, biological and synthetic studies. Herein, we describe the worldwide synthesis efforts towards this f...

The neem tree in the foreground of the cover picture is the natural source of azadirachtin, a complex molecule containing sixteen contiguous stereogenic centers, seven of which are tetrasubstituted carbon atoms. In their Communications starting on page 7629 ff., S. V. Ley et al. describe the conclusion of a long but successful journey culminating w...

(Chemical Equation Presented) 22 Years in the making: Azadirachtin (1) was synthesized for the first time by a highly convergent approach, utilizing a Claisen rearrangement and a radical cyclization as key steps. End-game strategies relied on intermediate 2, which could be obtained by synthetic methods as well as by degradation of 1. Bn = benzyl, T...

Nach 22 Jahren konnte die Totalsynthese von Azadirachtin (1) zum Abschluss gebracht werden. Die hoch konvergente Syntheseroute setzte auf eine Claisen-Umlagerung und eine radikalische Cyclisierung in den Schlüsselschritten. Die Endphase der Synthese stützte sich auf das Intermediat 2, das sowohl auf präparative Weise als auch durch Abbau von 1 erha...