Cycloaddition Reactions Of Nitrile Oxides Research Articles

Stereoselective intramolecular nitrile oxide cycloaddition to chiral allyl ethers

Intramolecular nitrile oxide cycloaddition reactions on (Z)- and (E)-chiral allyl ethers occur with poor to good stereoselectivity (diastereoisomeric ratios up to 86: 14), which depends on the double bond configuration as well as on steric and stereoelectronic effects.

Synthesis of the cis-decahydroquinoline ring system via an INOC reaction of a 1-acyldihydropyridine

Abstract The intramolecular nitrile oxide cycloaddition (INOC) reaction has been utilized in the synthesis of the cis -decahydroquinoline ring system.

The intramolecular nitrile oxide cycloaddition route to spirocyclic alkaloids. A total synthesis of isonitramine and sibirine

The Intramolecular nitrile oxide cycloaddition reaction has been found to accommodate the construction of spirocycles in modest yield as revealed by a synthesis of the title alkaloids.

The Reactions of Nitrile Oxides with Methoxy p-Benzoquinones

Abstract The 1,3-dipolar cycloaddition reactions of nitrile oxides with methoxy p-benzoquinones are discussed in terms of FMO theory. The unusual reaction pattern of methoxy p-benzoquinones with nitrile oxides is interpreted by considering both antibonding secondary orbital interaction and SHOMO(quinone)–LUMO (nitrile oxide) interaction.

Diastereofacial Selection in Nitrile Oxide Cycloaddition Reactions. The Anti-Directing Effect of an Allylic Oxygen and Some New Results on the Ring Metalation of Isoxazolines. A Synthesis of (±)-Blastmycinone.

The extent of diastereoselectivity associated with the reactions of nitrile oxides with alkenes bearing an allylic oxygen substituent has been studied. Reasonable levels of such diastereoselectivity have been found when the tert-butyldimethylsilyl ether derivative of 3-buten-2-ol (5) or (+)-(S)-isopropylidene-3-butene-1,2-diol (1) are employed as dipolarophiles. The stereochemical course of these cycloaddition reactions has been proven rigorously through the transformation of the adducts to known γ-lactones. The stereochemistry associated with the metalation/alkylation of 5-alkoxymethyl-substituted isoxazolines has also been probed in order to further expand the use of these heterocycles as aldol equivalents in natural products total synthesis. A synthesis of (±)-blastmycinone (34) is reported which combines the two foregoing aspects of stereocontrol. The levels of regio- and stereoselectivity found in the cycloaddition reactions of the cis- and trans-disubstituted alkenes 35 and 39 prepared from isopropylidene-D-glyceraldehyde are also discussed. A single example of the reaction of a chiral alkene with a chiral nitrile oxide is presented.

An Account of the Site- and Regio-selectivity in the Reaction of Nitrile Oxides with Substituted p-Benzoquinones by Frontier Molecular Orbital Theory

Abstract The 1,3-dipolar cycloaddition reactions of nitrile oxides with substituted p-benzoquinones are discussed in terms of Frontier Molecular Orbital (FMO) theory. The calculation is carried out by ab initio Self Consistent Field (SCF) method with STO-3G basis set. The site- and regio-selectivities in the reactions are correlated with two types of FMO interactions. Some predictions have been confirmed by experimental results.

The intramolecular nitrile oxide cycloaddition (INOC) route to the ergot alkaloids: Use of the isoxazoline to γ-amino alcohol conversion in the total synthesis of (+)-paliclavine

A total synthesis of the ergot alkaloid paliclavine ( 20 ), in optically active form is described. The synthesis scheme is based on the intramolecular dipolar cycloaddition reaction of a nitrile oxide to a neighboring olefinic appendage bearing an allylic asymmetric center. The extent of diastereofacial selection in the intramolecular nitrile oxide cycloaddition (INOC) reaction was found to be marginal. A single-crystal X-ray analysis has established the complete stereostructure of the isoxazoline 15 prepared from the “major” INOC product. The dependence of the reduction stereochemistry of the isoxazolinium salt 15a on the nature of the reducing agent is discussed.

The INOC approach to the hydroazulenone ring system - a potential entry tot he guaianolides and pseudoguaianolides.

The intramolecular nitrile oxide cycloaddition reaction has been examined as a method for preparing the hydroazulene ring system.

Diastereoselection in Intermolecular Nitrile Oxide Cycloaddition (NOC) Reactions: Confirmation of the "Anti-Periplanar Effect" through a Simple Synthesis of 2-Deoxy-d-ribose†.

Diastereoselection in Intermolecular Nitrile Oxide Cycloaddition (NOC) Reactions: Confirmation of the "Anti-Periplanar Effect" through a Simple Synthesis of 2-Deoxy-d-ribose†.

Zum Cycloadditionsverhalten von bis(trifluormethyl)substituierten Nitril-yliden [1]. Positionsselektivität und Regiochemie bei Abfangreaktionen mit Heterokumulenen / Cycloaddition Behaviour of Bis(trifluoromethyl) Substituted Nitrile Ylides [1]. Site Selectivity and Regiochemistry of Trapping Reactions with Heterocumulenes

2,2,2-Trimethoxy-3,3-bis(trifluoromethyl)-2,2-dihydro-1,4,2-oxazaphosphol-4-enes on thermolysis undergo a 1,3-dipolar cycloreversion reaction with formation of bis(trifluoromethyl) substituted nitrile ylides and trimethyl phosphate. The nitrile ylides are trapped by N-sulfinyl aniline, phenyl isocyanate, phenyl isothiocyanate, diphenyl ketene, and carbon disulfide. Site selectivity and regiochemistry of the [3 + 2]cycloaddition reactions are described. The results are compared with those obtained from [3 + 2]cycloaddition reactions of nitrile imines, nitrile oxides, alkyl, and aryl substituted nitrile ylides with heterocumulenes.

Diastereoface selection in the inoc reaction

The effect of an “inside” allylic asymmetric center on the course of the intramolecular nitrile oxide cycloaddition reaction has been studied.

Intramolecular nitrile oxide cycloaddition (INOC) reactions in the indole series. 2. Total synthesis of racemic and optically active paliclavine and 5-epi-paliclavine

Intramolecular nitrile oxide cycloaddition (INOC) reactions in the indole series. 2. Total synthesis of racemic and optically active paliclavine and 5-epi-paliclavine

Some Aspects for 1,3-Dipolar Cycloaddition Reaction of Nitrile Oxide with Methyl Crotonate in the Synthesis of Carbapenam Antibiotics

Some Aspects for 1,3-Dipolar Cycloaddition Reaction of Nitrile Oxide with Methyl Crotonate in the Synthesis of Carbapenam Antibiotics

1,3‐Dipolar cycloadditions of cyclopentadienones with nitrile TV‐oxides

AbstractThe cycloaddition reactions of nitrile oxides with several substituted cyclopentadienones leads to the formation of condensed mono‐isoxazolines (3α,5‐bis‐substituted‐6,6α‐diphenyl‐3αH,4H,6αH‐cyclopenta[2,3‐d]isoxazol‐4‐ones) and in some cases to bis‐isoxazoline derivatives as minor products. The cycloaddition to mono‐adducts is regioselective and only one regioisomer is formed, which can be predicted after consideration of the frontier molecular orbitals of the reacting species. The spectral data of the isoxazolines 3–7 are examined, whereas their structure was fully characterized by X‐ray analysis.