Nitroso Diels-Alder Reaction Research Articles

Synthesis of the Cyclopentane Core Skeleton of Cranomycin and Jogyamycin.

Cranomycin and jogyamycin, two aminocyclopentitol natural products, possess complex structures and potential medicinal properties. This review describes synthetic studies about the process of making an advanced intermediate of cranomycin and jogyamycin. This highly functionalized intermediate, featuring three contiguous amine-substituted stereocenters, was constructed from cyclopentadiene through a series of reactions including the nitroso Diels-Alder reaction, nitrogen radical cyclization reaction, 1,2-nitrogen migration, and stereoselective nitrogen addition.

Organocatalytic Highly Selective Nitroso-Diels–Alder Reaction of Conjugated Trienes

Organocatalytic Highly Selective Nitroso-Diels–Alder Reaction of Conjugated Trienes

Diastereoselective acyl nitroso Diels-Alder reactions using 1,3-dienes derived from (R)-4-tert-butyldimethylsilyloxy-2-cyclohexen-1-one

1,3-Dienes derived from (R)-4-t-butyldimethylsilyloxy-2-cyclohexen-1-one react with acyl nitroso dienophiles to form exclusively anti [4 + 2] cycloaddition products. These regio and diastereoselective acyl nitroso Diels-Alder reactions increase the asymmetric complexity from one chiral center in the starting material to three chiral centers in the products in a single step and provide a powerful approach for the asymmetric synthesis of compounds containing 3,6-dihydro-1,2-oxazine structural feature.

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition.

A convergent strategy for the synthesis of leustroducsins and phoslactomycins has been designed, relying on the synthesis and the coupling of three main fragments. The central fragment was synthesized via a regio-and stereoselective nitroso Diels–Alder reaction with an enol phosphate, followed by reductive cleavage of the phosphate to the ketone 11b. Coupling studies of this fragment with the lactone fragment was accomplished in a stereoselective fashion through a vinyllithium intermediate. An advanced synthetic intermediate was then obtained after functional group transformation.

Design and Synthesis of C-1 Methoxycarbonyl Derivative of Narciclasine and Its Biological Activity.

A 15-step chemoenzymatic total synthesis of C-1 methoxycarbonyl narciclasine (10) was accomplished. The synthesis began with the toluene dioxygenase-mediated dihydroxylation of ortho-dibromobenzene to provide the corresponding cis-dihydrodiol (12) as a single enantiomer. Further key steps included a nitroso Diels–Alder reaction and an intramolecular Heck cyclization. The C-1 homolog 10 was tested and evaluated for antiproliferative activity against natural narciclasine (1) as the positive control. Experimental and spectral data are reported for all novel compounds.

Chiral Gold Complex Catalyzed Cycloisomerization/Regio- and Enantioselective Nitroso-Diels–Alder Reaction of 1,6-Diyne Esters with Nitrosobenzenes

Chiral Gold Complex Catalyzed Cycloisomerization/Regio- and Enantioselective Nitroso-Diels–Alder Reaction of 1,6-Diyne Esters with Nitrosobenzenes

The Application of 1,2-Oxazinanes as Chiral Cyclic Weinreb Amide-Type Auxiliaries Leading to a Three-Component, One-Pot Reaction

Abstract1,2-Oxazines were synthesised via a copper-catalysed aerobic acyl nitroso Diels–Alder reaction from 1,4-disubstituted 1,3-dienes and N-Boc-hydroxylamine. From this, 1,2-oxazinanes were obtained in a novel follow-up reaction path. The stability of several 1,2-oxazines and 1,2-oxazinanes towards organometallic compounds was tested to rate their operability as cyclic chiral Weinreb amide auxiliaries. 3,6-Di-tert-butyl-1,2-oxazinane gave the best results and was introduced as a chiral Weinreb amide-type auxiliary to yield chiral α-substituted ketones in a diastereomeric ratio of up to 98:2. The removal of the auxiliary can be performed with BuLi to form unsymmetrical α-chiral ketones. Thereafter, the chiral auxiliary can be re-isolated and purified by sublimation under vacuum.

Synthesis and biological evaluation of 10-benzyloxy-Narciclasine

A chemoenzymatic convergent synthesis of 10-benzyloxy narciclasine from bromobenzene was accomplished in 16 steps. The key transformations included toluene dioxygenase-mediated hydroxylation, nitroso Diels-Alder reaction and intramolecular Heck cyclization. The unnatural derivative of narciclasine was subjected to biological evaluation and its activity was compared to other C-10 and C-7 compounds prepared previously.

Alternating Current Electrolysis as Efficient Tool for the Direct Electrochemical Oxidation of Hydroxamic Acids for Acyl Nitroso Diels-Alder Reactions.

The acyl nitroso Diels–Alder reaction of 1,3‐dienes with electrochemically oxidised hydroxamic acids is described. By using alternating current electrolysis, their typical electro‐induced decomposition could be suppressed in favour of the 1,2‐oxazine cycloaddition products. The reaction was optimised using Design of Experiments (DoE) and a sensitivity test was conducted. A mixture of triethylamine/hexafluoroisopropanol served as supporting electrolyte in dichloromethane, thus giving products of high purity after evaporation of the volatiles without further purification. The optimised reaction conditions were applied to various 1,3‐dienes and hydroxamic acids, giving up to 96 % isolated yield.

Ring Opening Metathesis Polymerization of a New Monomer Derived from a Nitroso Diels–Alder Reaction

Front Cover: In article number 2100098, Christopher E. Hobbs and co-workers describe the use of a Nitroso–Diels–Alder reaction as an effective route toward the synthesis of modifiable, hydroxyl-and amino-decorated polymeric materials using ring opening metathesis polymerization (ROMP).

Ring Opening Metathesis Polymerization of a New Monomer Derived from a Nitroso Diels–Alder Reaction

AbstractA nitroso Diels–Alder (NDA) reaction between cyclopentadiene and an in situ generated nitroso compound leads to a new heterocyclic monomer for ring opening metathesis polymerization (ROMP) reactions. This monomer could be polymerized in the presence of Grubbs‐third generation initiator with good control over Mn and decent Ð values. The resulting isoxazolidine‐containing material could undergo further hydrogenation, deprotection, and modification with Dansyl chloride as well as ring opening to provide an amino‐and hydroxyl‐decorated “polyolefin.”

Davis–Beirut reaction inspired nitroso Diels–Alder reaction

A Davis–Beirut reaction inspired nitroso Diels–Alder protocol is reported. The starting material for the procedure is a nitrophenyl moiety with the para position appropriately substituted with a 2°-amine (see 5) or 2°-alcohol (see 6). Deprotonation at the benzylic position followed by concomitant oxidation of the benzylic position and reduction of the nitro moiety delivers a nitrosophenyl intermediate, which subsequently undergoes a nitroso Diels–Alder reaction. This one-pot procedure delivers aryldihydro-1,2-oxazines in moderate yields.

Nitroso Diels-Alder Cycloadducts Derived From N-Acyl-1,2-dihydropyridines as a New Platform to Molecular Diversity.

This review focuses upon the use of nitroso Diels–Alder reactions as a structural complexity generating reaction that has been so far a quite scarcely treated topic, despite its potential. In particular, the use of N-acyl-1,2-dihydropyridines as a non-symmetrical diene component in nitroso Diels–Alder reactions encompasses an initial diversification of pathways giving rise to different cycloadducts (direct and inverse). Selective elaborations of these cycloadducts, basically using a reagent-based approach, deliver a discrete number of structurally diverse compounds, including some original heterobicyclic scaffolds and functionalized heterocycles. This forward synthetic planning allowed the individuation of a new biologically active compound based on a novel oxadiaza-bicyclic-[3.3.1]-nonene scaffold which is still under preclinical evaluation.

Erratum to: Recent Advances in Asymmetric Nitroso Diels-Alder Reactions

Erratum to: Recent Advances in Asymmetric Nitroso Diels-Alder Reactions

Recent Advances in Asymmetric Nitroso Diels—Alder Reactions

The nitroso Diels—Alder (NDA) reaction has occupied an important place in organic synthesis, and numbers of important compounds and bioactive skeletons have been synthesized by this method during the past decade. Good regiocontrol and enantioselectivity of the NDA reaction allow it to have wider application. This microreview discusses the latest advances in the area of asymmetric NDA reactions and their synthetic applications since Yamamoto’s detailed summary made in 2006.

Copper(i)/TF-BiphamPhos catalyzed asymmetric nitroso Diels-Alder reaction.

A highly efficient enantioselective nitroso Diels-Alder reaction of 6-methyl-2-nitroso pyridine with various 1,3-dienes was successfully developed using a Cu(i)/(S)-TF-BiphamPhos complex as the catalyst. For most of the cyclic dienes, synthetically important heterocyclic 3,6-dihydro-1,2-oxazines were obtained in high yields with excellent regio-, diastereo- and enantioselectivities. Acyclic 2-silyloxy-1,3-diene also worked well in the reaction.

Asymmetric Oxidative Nitroso-Diels-Alder Reaction of N-Arylhydroxylamines Catalyzed by a Chiral Phosphoric Acid.

A highly stereoselective synthesis of cis-3,6-disubstituted dihydro-1,2-oxazines has been accomplished through the one-pot oxidative nitroso-Diels-Alder reaction of N-arylhydroxylamines with diene carbamates. The new system is based on a combination of chiral phosphoric acid and m-CPBA and gives various 3,6-disubstituted dihydro-1,2-oxazines in excellent regio-, diastereo-, and enantioselectivity.

Catalytic Enantioselective Nitroso Diels-Alder Reaction.

The nitroso Diels-Alder (NDA) reaction is an attractive strategy for the synthesis of 3,6-dihydro-1,2-oxazines and 1-amino-4-hydroxy-2-ene derivatives. Herein we report the Cu(I)-DTBM-Segphos catalyzed asymmetric intermolecular NDA reaction of variously substituted cyclic 1,3-dienes using highly reactive nitroso compounds derived from pyrimidine and pyridazine derivatives. In most of the cases studied, the cycloadducts were obtained in high yields (up to 99%) with very high regio-, diastereo-, and enantioselectivities (up to regioselectivity > 99:1, d.r. > 99:1, and >99% ee). As an application of this methodology, formal syntheses of conduramine A-1 and narciclasine were accomplished.

Regio-, Diastereo-, and Enantioselective Nitroso-Diels-Alder Reaction of 1,3-Diene-1-carbamates Catalyzed by Chiral Phosphoric Acids.

Chiral phosphoric acid-catalyzed asymmetric nitroso-Diels-Alder reaction of nitrosoarenes with carbamate-dienes afforded cis-3,6-disubstituted dihydro-1,2-oxazines in high yields with excellent regio-, diastereo-, and enantioselectivities. Interestingly, we observed that the catalyst is able not only to control the enantioselectivity but also to reverse the regioselectivity of the noncatalyzed nitroso-Diels-Alder reaction. The regiochemistry reversal and asynchronous concerted mechanism were confirmed by DFT calculations.

Continuous flow of nitroso Diels-Alder reaction.

Our flow reaction systems have provided quantitative yields of nitroso Diels-Alder products with no byproducts in cases of cyclic dienes without temperature and pressure controls. Additionally, the reaction times were significantly shortened by using homogeneous catalyst (CuCl) or heterogeneous reagent (MnO2) in comparison with batch reaction.