Synthesis Of Azadirachtin Research Articles

Light-Driven Metal-Free Direct Deoxygenation of Alcohols under Mild Conditions.

SummaryHydroxyl is widely found in organic molecules as functional group and its deprivation plays an inevitable role in organic synthesis. However, the direct cleavage of Csp3-O bond in alcohols with high selectivity and efficiency, especially without the assistance of metal catalyst, has been a formidable challenge because of its strong bond dissociation energy and unfavorable thermodynamics. Herein, an efficient metal-free strategy that enables direct deoxygenation of alcohols has been developed for the first time, with hydrazine as the reductant induced by light. This protocol features mild reaction conditions, excellent functional group tolerance, and abundant and easily available starting materials, rendering selective deoxygenation of a variety of 1° and 2° alcohols, vicinal diols, and β-1 and even β-O-4 models of natural wood lignin. This strategy is also highlighted by its “traceless” and non-toxic by-products N2 and H2, as readily escapable gases. Mechanistic studies demonstrated dimethyl sulfide being a key intermediate in this transformation.

Challenges for the Synthesis of Azadirachtin

Challenges for the Synthesis of Azadirachtin

ChemInform Abstract: Asymmetric Formal Synthesis of Azadirachtin.

An asymmetric formal synthesis of azadirachtin, a potent insect antifeedant, was accomplished in 30 steps to Ley's synthetic intermediate (longest linear sequence). The synthesis features: 1) rapid access to the optically active right-hand segment starting from the known 5-hydroxymethyl-2-cyclopentenone scaffold; 2) construction of the B and E rings by a key intramolecular tandem radical cyclization; 3) formation of the hemiacetal moiety in the C ring through the α-oxidation of the six-membered lactone followed by methanolysis.

Second‐Generation Synthesis of Azadirachtin: A Concise Preparation of the Propargylic Mesylate Fragment

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 controls the installation of the remaining functionality in a total of only 17 steps.

Second‐Generation Synthesis of Azadirachtin: A Concise Preparation of the Propargylic Mesylate Fragment

AbstractNeuer Anlauf: Eine hocheffiziente Synthese des Propargylmesylat‐Fragments von Azadirachtin wurde entwickelt (siehe Schema; Bn=Benzyl, Ms=Methansulfonyl, PMB=para‐Methoxybenzyl, TBDPS=tert‐Butyldiphenylsilyl). Eine enantioselektive katalytische Hetero‐Diels‐Alder‐Reaktion liefert das C15‐Stereozentrum, das anschließend den weiteren Aufbau des Moleküls in insgesamt nur 17 Stufen steuert.magnified image

ChemInform Abstract: Synthesis of Azadirachtin: A Long but Successful Journey.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of Azadirachtin: A Long but Successful Journey

Synthesis of Azadirachtin: A Long but Successful Journey

Synthesis of Azadirachtin: A Long but Successful Journey

Synthesis of Azadirachtin: A Long but Successful Journey

AZADIRACHTIN AT LAST

IT TOOK 22 YEARS and the efforts of more than 40 chemists, but Steven V. Ley's group has finally managed to complete a 64-step synthesis of azadirachtin, a naturally occurring insecticide ( Angew. ...

Studies Toward the Synthesis of Azadirachtin. Part 1. Total Synthesis of a Fully Functionalized ABC Ring Framework and Coupling with a Norbornene Domain

AbstractFor Abstract see ChemInform Abstract in Full Text.

Studies Toward the Synthesis of Azadirachtin. Part 2. Construction of Fully Functionalized ABCD Ring Frameworks and Unusual Intramolecular Reactions Induced by Close‐Proximity Effects.

The remarkable antifeedant agent and insecticide, azadirachtin (1), has, to date, escaped a total synthesis. The preparation of an advanced precursor has revealed some of the inner intricacies of this uniquely crowded and highly functionalized molecular architecture.

Studies toward the Synthesis of Azadirachtin, Part 2: Construction of Fully Functionalized ABCD Ring Frameworks and Unusual Intramolecular Reactions Induced by Close‐Proximity Effects

Das bemerkenswerte fraßhemmende Agens und Insektizid Azadirachtin (1) (siehe Formel) ist bis heute nicht durch Totalsynthese zugänglich. Das Herstellen einer komplexen Vorstufe enthüllte einige der inneren Feinheiten dieser einzigartig sterisch belasteten und hoch funktionalisierten Molekülarchitektur.

Studies toward the Synthesis of Azadirachtin, Part 1: Total Synthesis of a Fully Functionalized ABC Ring Framework and Coupling with a Norbornene Domain

Das komplexe Decalin-Intermediat 1 wurde synthetisiert und in die potenzielle Azadirachtin-Vorstufe 2 überführt. Zu dieser herausfordernden Synthese gehörten mehrere Schutzgruppenmanipulationen und das Kuppeln von 1 mit einer geeigneten Norborneneinheit.

Studies toward the Synthesis of Azadirachtin, Part 2: Construction of Fully Functionalized ABCD Ring Frameworks and Unusual Intramolecular Reactions Induced by Close‐Proximity Effects

The remarkable antifeedant agent and insecticide, azadirachtin (1), has, to date, escaped a total synthesis. The preparation of an advanced precursor has revealed some of the inner intricacies of this uniquely crowded and highly functionalized molecular architecture.

Studies toward the Synthesis of Azadirachtin, Part 1: Total Synthesis of a Fully Functionalized ABC Ring Framework and Coupling with a Norbornene Domain

Studies toward the Synthesis of Azadirachtin, Part 1: Total Synthesis of a Fully Functionalized ABC Ring Framework and Coupling with a Norbornene Domain

Studies Towards the Synthesis of Azadirachtin: Enantioselective Entry into the Azadirachtin Framework Through Cascade Reactions.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Studies Towards the Synthesis of Azadirachtin: Enantioselective Entry into the Azadirachtin Framework through Cascade Reactions

The carbon framework of azadirachtin (1) has been prepared enantioselectively: The synthesis of compounds 2 a–c follows two novel cascade sequences based on intramolecular radical reactions and acid-mediated redox chemistry. Such advanced intermediates should allow access to 1 through appropriate functional-group manipulations.

Studies Towards the Synthesis of Azadirachtin: Enantioselective Entry into the Azadirachtin Framework through Cascade Reactions

Studies Towards the Synthesis of Azadirachtin: Enantioselective Entry into the Azadirachtin Framework through Cascade Reactions

Chemistry of insect antifeedants from azadirachta indica (part 6): Synthesis of an optically pure acetal intermediate for potential use in the synthesis of azadirachtin and novel antifeedants.

For potential use in a synthesis of the antifeedant azadirachtin ( 1) and novel antifeedants, a key tricyclic acetal intermediate ( 2) has been prepared in optically pure form in 12 steps from the known (−)−3-endo-bromotricyclo[3.2.0.0 2,7]heptan-6-one ( 3).