1,721,064 research outputs found
Green Three-Component Approach to 2-Phenyl-4- Acetoxybenzoate Derivatives as Intermediates in the Synthesis of Pharmaceuticals
No full text
Cicloeterificazione di fenilselenonil alcooli: Sintesi Stereoselettiva di Isocromani e Tetraidropirani
No full textViene riportata la sintesi stereoselettiva di isocromani e tetraidropirani sostituiti ottenuti via anellazione mediante sostituzione nucleofila intramolecolare del gruppo fenilselenonile da parte dell’ossigeno ossidrilico. Questa cicloeterificazione rappresenta il primo esempio di utilizzo dei selenoni per la sintesi di anelli tetraidropiranic
High Pressure Diels-Alder Approach to Biaryls and Heterobiaryls: a New Multicomponent Metal-Free Route
No full textSynthesis and Functionalization via Direct Lithiation of α-Aryl-substituted Tetrahydropyrans
No full textThree-component and Metal – Free Route to Substituted Biaryls and Heterobiaryls under High Pressure Conditions
No full textAn efficient and metal-free synthesis of biaryls and heterobiaryls, via a key multicomponent reaction of benzylideneacetones, isopropenyl acetate and methyl propiolate under high pressure (9 Kbar) and mild reaction temperature (45 °C) conditions was affected
Exploration of Synthetic Strategies for the Preparation of Novel Tetrahydrofuran-containing Biaryls via Diels-Alder Reaction
No full textA straightforward synthesis of functionalized 6H-benzo[c]chromenes from 3-alkenyl chromenes by intermolecular Diels-Alder/aromatization sequence
No full text: A new and metal-free approach to the synthesis of substituted 6H-benzo[c]chromenes has been developed. This three-step synthetic sequence starts from variously substituted salicylaldehydes and α,β-unsaturated carbonyl compounds to form the chromene core. The de novo ring-forming key step is based on a highly regioselective intermolecular Diels-Alder cycloaddition between 3-vinyl-2H-chromenes and methyl propiolate, followed by oxidative aromatization of the cyclohexadiene cycloadduct intermediate to obtain the final products in good yields (up to 94% over two steps). A modular and divergent design was followed, including a multicomponent reaction, to maximize the scaffold diversity obtained from our approach. The mechanism, investigated by DFT calculations, was confirmed to be concerted through a slightly asynchronous transition state. Energetic analysis of the transition states which have been found confirmed the experimental results in terms of regioselectivity and reactivity tendencies
Multicomponent high pressure promoted Diels-Alder reactions: metal-free access to biaryls and heterobiaryls
No full textRecent advances in chemoselective acylation of amines
No full textN-chemoselective acylation of amines in the presence of competing nucleophiles, like alcohols and thiols,
is by no means a simple achievement in organic synthesis and even more difficulties arise when distinctions
between primary, secondary, and aromatic amines need to be made. The present digest will review
some recent achievements in this field, ranging from transamidation reactions to carboxylic acid derivatives
transacylations. In addition, more creative strategies, involving chemoenzymatic reactions and
metal-catalyzed acylations and carbonylations, will be discussed in order to furnish a concise view of
the state-of-the-art approaches to this synthetic challenge
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