A Straightforward Synthesis of Enantiopure Bicyclic Azetidines

Mangaleswaran, Sivaprakasam; Couty, François; David, Olivier; Marrot, Jérôme; Ramaswamy, Sridhar; Srinivas, B.; Rao, K. Rama

doi:10.1002/ejoc.200700616

Cited by 24 publications

(14 citation statements)

References 19 publications

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“…Rewardingly, the simple and stable Gagosz catalyst smoothly provided the expected azabicyclic product 2 a in 50 % yield with 10 equivalents of phenol (Table , entry 1). Tuning of the ligand properties did not improve this result (Table , entries 2–6), whereas counterion variations had a strong effect (entries 7–9).…”

Section: Methodsmentioning

confidence: 99%

Gold(I)‐Catalyzed N‐Desulfonylative Amination versus N‐to‐O 1,5‐Sulfonyl Migration: A Versatile Approach to 1‐Azabicycloalkanes

et al. 2016

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Valuable 1-azabicycloalkane derivatives have been synthesized through a novel gold(I)-catalyzed desulfonylative cyclization strategy. An ammoniumation reaction of ynones substituted at the 1-position with an N-sulfonyl azacycle took place in the presence of a gold cation by intramolecular cyclization of the disubstituted sulfonamide moiety onto the triple bond. Depending on the size of the heterocyclic ring and substitution of the substrates, two unprecedented forms of nucleophilic attack on the sulfonyl group were exploited, that is, a N-desulfonylation in the presence of an external protic O nucleophile (37-87 %, 10 examples) and a unique N-to-O 1,5-sulfonyl migration (60-98 %, 9 examples).

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Section: Methodsmentioning

confidence: 99%

Gold(I)‐Catalyzed N‐Desulfonylative Amination versus N‐to‐O 1,5‐Sulfonyl Migration: A Versatile Approach to 1‐Azabicycloalkanes

et al. 2016

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“…However, other groups were found to allow such anionic ring closure, such as esters, [13,14] phosphonates, and phosphane oxides. Concerning this point, we were quite lucky with our initial experiments, as we began our investigation with α-amino nitriles (EWG = CN), which proved retrospectively to be by far the more reactive, easy to introduce, and versatile group.…”

Section: Synthesis Of Azetidines Through Anionic C-alkylationmentioning

confidence: 99%

“…In the case of alkyl-substituted β-amino alcohols, it is also possible, by using mild chlorination conditions, to promote kinetic control and to prepare selectively the β-amino chloride, which results from kinetic opening of the aziridinium ion (primary chloride 21), as shown in Scheme 3. [14] Scheme 3. Kinetic control in the chlorination of an alkyl-substituted β-amino alcohol.…”

Section: Synthesis Of Azetidines Through Anionic C-alkylationmentioning

confidence: 99%

“…Concerning this point, we were quite lucky with our initial experiments, as we began our investigation with α-amino nitriles (EWG = CN), which proved retrospectively to be by far the more reactive, easy to introduce, and versatile group. However, other groups were found to allow such anionic ring closure, such as esters, [13,14] phosphonates, and phosphane oxides. [15] Very recently, a simple N-benzylic position was shown to behave as a possible nucleophile upon deprotonation with LiDA-KOR [16] [Scheme 4, Eq.…”

Section: Synthesis Of Azetidines Through Anionic C-alkylationmentioning

confidence: 99%

“…(6)]. Thus, N-alkylation of 88 with methyl trifluoromethanesulfonate gave 89, and ring opening of this bicyclic ammonium ion occurred regioselectively [14] to give azepanes 90-92 (Scheme 16). Azepanes can also be produced by anionic rearrangement from properly substituted azetidinium ions such as 93 and 94.…”

Section: Ring Expansion Of Azetidinesmentioning

confidence: 99%

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2‐Cyanoazetidines and Azetidinium Ions: Scaffolds for Molecular Diversity

et al. 2013

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Ring strain in azetidines and azetidinium ions can be efficiently used to promote ring‐expansion and ring‐opening reactions, and this renders these four‐membered heterocycles ideal scaffolds for diversity oriented synthesis. This microreview focuses on 2‐cyanoazetidines, which are easily prepared from β‐amino alcohols through a ring‐closing reaction involving C–C bond formation. The azetidines can be readily expanded to five‐ to eight‐membered nitrogen heterocycles after suitable functionalization and/or activation. Alternatively, N‐alkylated derivatives, namely, azetidinium ions, are easily prepared and displayed rich reactivity as new electrophilic building blocks and as sources of nitrogen ylides.

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Carboamination and Alkylative Cyclization withCNBond Formation in Stereoselective Syntheses

Ghorai

Halder

Samanta

2013

Stereoselective Synthesis of Drugs and Natural Products

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The carboamination reaction can be considered an important and fascinating tool for atom‐economic and convergent construction toward the functionalized N ‐containing cyclic compounds. Because the aza‐cycle is frequently found in almost all members of the alkaloid family with immense synthetic and pharmacological activities, the formation of this ring system is a highly demanding task for synthetic organic chemists. As a result, several rational techniques have been developed including intramolecular S N 2 reactions, reductive amination reactions, conjugate addition reactions, metal‐ and acid‐catalyzed cyclizations, and ring‐closing olefin metathesis reactions. Despite the many available routes, the carboamination strategy could be one of the best techniques considering stereoselectivity and the step economic path toward the formation of ring compounds in an elegant way.Alkylative cyclization with CN bond formation ( N ‐alkylation) is one of the most important methods in organic synthesis for the construction of aza‐cycles. Many well‐known name reactions (e.g., aza‐Diels‐Alder, aza‐Michael, aza‐Mannich, aza‐Henry reactions, etc.), which are generally being employed in the intramolecular CN bond formation step, can be treated as CN alkylative cyclization. It is an extremely powerful method for the stereoselective synthesis of N ‐heterocycles like aziridines, azetidines, lactams, pyrrolidines, piperidines, amino sugars, and many more, which are the basic structural units present in many natural products and biologically active compounds.

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A Straightforward Synthesis of Enantiopure Bicyclic Azetidines

Cited by 24 publications

References 19 publications

Gold(I)‐Catalyzed N‐Desulfonylative Amination versus N‐to‐O 1,5‐Sulfonyl Migration: A Versatile Approach to 1‐Azabicycloalkanes

Gold(I)‐Catalyzed N‐Desulfonylative Amination versus N‐to‐O 1,5‐Sulfonyl Migration: A Versatile Approach to 1‐Azabicycloalkanes

2‐Cyanoazetidines and Azetidinium Ions: Scaffolds for Molecular Diversity

Carboamination and Alkylative Cyclization withCNBond Formation in Stereoselective Syntheses

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