A Convenient Synthesis of 3,3-Dichloroazetidines, a New Class of Azetidines

Aelterman, Wim; Kimpe, Norbert De; Declercq, Jean‐Paul

doi:10.1021/jo970342w

Cited by 44 publications

(23 citation statements)

References 26 publications

(38 reference statements)

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“…After mesylation of the -hydroxyimines with mesyl chloride in pyridine, the cis-azetidines 48 were generated either via a nucleophile-induced one-step cyclization or in a two-step sequence consisting of a reduction with sodium cyanoborohydride followed by a ring closure under basic conditions (Scheme 16). 42 Exclusively cis-2,4-diaryl-3,3-dichloroazetidines 48 were observed. The observed stereoselectivity was described via an Evans-type model, where the nucleophile forming the new bond and the larger aryl substituent R A are situated most remote from each other (Scheme 17).…”

Section: Synthesis Of Azetidinesmentioning

confidence: 98%

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1-Azaallylic Anions in Heterocyclic Chemistry

2004

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Section: Synthesis Of Azetidinesmentioning

confidence: 98%

“…When N-(2,2-dichloro-1-phenylethylidene)isopropylamine (27) was reacted with 2-ethylbutanal, a 1:1 mixture of cis-and trans-2-chloro-2-imidoyloxiranes 28 was obtained (Scheme 11). 42 Oxiranylimines 29 can suffer base-induced dimerization to give aziridine 31 as the sole diastereoisomer (Scheme 12). 43 …”

Section: Synthesis Of Oxiranesmentioning

confidence: 99%

1-Azaallylic Anions in Heterocyclic Chemistry

2004

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“…3,3-Dichloro-1-azaallylic anions, derived from α,α-dichloroketimines 4g,h by deprotonation with LDA, undergo an aldol reaction with aromatic aldehydes to give adducts, which, upon activation as mesylates, are conveniently converted into cis-3,3-dichloroazetidines 39a-c and 40a-c [19] by reaction with sodium borohydride or potassium cyanide (Scheme 11). The stereospecific formation of cis-azetidines 39a-c and 40a-c is explained by an Evans-type model of transition state, favoring the attack of the imino bond to occur from the site most remote from the larger substituent (Scheme 12).…”

Section: Methodsmentioning

confidence: 99%

Use of 3‐Halo‐1‐azaallylic Anions in Heterocyclic Chemistry

2004

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Abstract:The synthetic potential of lithio 3-halo-1-azaallylic anions as building blocks in organic chemistry and especially in heterocyclic chemistry will be highlighted by the synthesis of functionalized imines, obtained after reaction of 3-halo-1-azaallylic anions with heteroatom-substituted electrophiles. Thus, the latter generated functionalized imines are suitable building blocks for the synthesis of a whole range of heterocycles and physiologically active compounds, including agrochemicals and pharmaceuticals. 3-Halo-1-azaallylic anions were used in the synthesis of N-alkyl-3,3-dichloroazetidines, 2,3-disubstituted pyrroles, piperidines, 2-substituted pyridines, 2-alkoxytetrahydrofurans, etc., from which a large range of useful and interesting chemicals can be produced, e.g., 2-azetines and 9-alkyl-2-phenyl-3aβ, 4,6,7,8,9,9aβ,9bβ-octahydro-1H-pyrrolo[3,4,h]quinoline-1,3-diones. The utility of the present methodology is demonstrated by the synthesis of the pheromone (S)-manicone, the sulfur-containing flavor compound 2-[(methylthio)methyl]-2-butenal, and some agrochemical and pharmaceutical compounds.

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“…[363,364] A wide variety of electrophiles have been used to alkylate 3-chloro-1-azaallylic anions, inter alia benzaldehydes, [365] ø-iodoalkyl azides, [299] and 2-bromo-1-(trimethylsiloxy)ethane [127,366] can be mentioned. Treatment of AE-bromo imines bearing no acidic AE-protons with lithium diisopropylamide in tetrahydrofuran, [367] methyllithium, or methylcopper [368] affords 1,4-diimines via an electron-transfer dehydrodimerization process.…”

Section: C-alkylation Of 1-azaallyl Anions With Alkyl Halidesmentioning

confidence: 99%

Product Class 7: Imines

Padwa¹,

Bellus²

2005

Category 4. Compounds With Two Carbon Heteroatom Bonds

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Compounds with the general structure R 1 R 2 C=NR 3 , referred to as imines, were first obtained by Schiff via condensation of ketones and aldehydes with primary amines. Therefore, the condensation products are also called Schiff bases. In addition, the nominations azomethine, ketimine (derived from ketones), aldimine (derived from aldehydes), and anil (derived from anilines) are in use. It is recommended that the terms imine(s), ketimine(s), or aldimine(s) are used, rather than Schiff base(s) or azomethine(s).Since imines have to be considered as analogues of carbonyl compounds, many of the chemical properties are similar to the latter. Imines are used in new C-C bond formations, and reactions with electrophiles (e.g., aldehydes, alkyl halides), and the C=N moiety can undergo nucleophilic reactions. Generally, imines are very useful compounds in organic synthesis, as they are used in several syntheses of aza-heterocyclic compounds. Most imines are stable in an alkaline medium and therefore can be dried over potassium hydroxide. In diluted acid, however, they are easily hydrolyzed. In many cases intermediary imines cannot be isolated because of their lability. The presence of a C=N bond creates the possibility for E/Z isomerism (syn/anti). It has been recognized that such geomet-

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A Convenient Synthesis of 3,3-Dichloroazetidines, a New Class of Azetidines

Cited by 44 publications

References 26 publications

1-Azaallylic Anions in Heterocyclic Chemistry

1-Azaallylic Anions in Heterocyclic Chemistry

Use of 3‐Halo‐1‐azaallylic Anions in Heterocyclic Chemistry

Product Class 7: Imines

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