Indolizidine Derivatives Research Articles

Synthesis of Pyrrolizidine, Indolizidine, and Quinolizidine Derivatives Using Ruthenium‐Catalyzed Ring‐Opening Metathesis and Ring‐Closing Metathesis of Cycloalkene‐ynes

AbstractRing‐opening metathesis and ring‐closing metathesis (ROM‐RCM) of a cyclopentene‐yne having an ester moiety was demonstrated using first‐ and second‐generation Grubbs’ catalysts. When the reaction of cycloalkene‐yne was carried out in the presence of 5 mol % of a ruthenium carbene complex under an ethylene atmosphere at room temperature, ROM‐RCM proceeded smoothly to give a pyrrolidine derivative in good yield, which could be converted to a pyrrolizidine derivative. Furthermore, ROM‐RCM of azabicyclo[2.2.1]heptene‐ynes using the second‐generation Grubbs’ catalyst was investigated. When an azabicycloheptene derivative was exposed to a catalytic amount of a ruthenium carbene complex, pyrrolizidine and indolizidine derivatives were obtained in good yields. The distribution of these products depends on the substituents on the alkyne. When azabicyclo[2.2.1]heptene‐ynes bearing large substituents on the alkyne were treated with ruthenium catalyst 1b, a pyrrolizidine derivative was obtained as the major product. ROM‐RCM of azabicyclo[2.2.2]octene‐ynes with 1b afforded quinolizidine derivative 20, although the yield was moderate.

ROM–RCM of azabicycloheptene derivatives—Study of products distribution by the substituent on alkyne

ROM–RCM (ring-opening metathesis and ring-closing metathesis) of azabicyclo[2.2.1]heptene-ynes using the second-generation Grubbs catalyst was investigated. When an azabicycloheptene derivative was exposed to a catalytic amount of a ruthenium carbene complex, pyrrolizidine and indolizidine derivatives were obtained in good yields. The distribution of these products depends on the substituents on the alkyne.

Tuning the Acceptors in Catalyzed Cyclizations Initiated by Allenes. Silylstannylation/Cyclization of Allene-Aldehydes for Synthesis of Polyalkylated Indolizidines Including 223A Congeners

Starting from succinamide and 1,2-heptadiene-4-ol, a racemic allene-aldehyde substrate, 20, suitable for R(3)SiSnR'(3)-mediated cyclization was synthesized in six steps and in 21% yield. Stereoselective cyclization (relative cis configuration at the new stereogenic centers of the homoallyl alcohol generated) proceeded smoothly, giving a mixture of indolizidinols bearing five contiguous stereocenters in a combined yield of 80%. Relative configurations of each of the products were unequivocally established by a combination of 2D NMR experiments and single-crystal X-ray analysis. The major indolizidinol obtained in 32% yield was elaborated into indolizidine 5,8-epi-indolizidine 223A via a five-step reaction sequence in 32% overall yield. The second major component (24%) of the key cyclization yielded, in four steps, indolizidine 6,8-epi-223 in 14% yield. Even though revision of the initially postulated structure foiled our original synthetic plans for the natural product, indolizidine 223A, the new stereoselective cyclization strategy and several selective transformations of the indolizidine derivatives reported here may find further applications for the synthesis of highly alkylated indolizidine and other related alkaloids.

Synthesis of Optically Active Trifluoromethylated Indolizidine Derivatives via Stereoselective Radical Cyclization.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of optically active trifluoromethylated indolizidine derivatives via stereoselective radical cyclization.

[reaction: see text]. Asymmetric Michael reaction of lithiated trifluoroacetone SAMP-hydrazone with alkylidenemalonates gave addition products stereoselectively. Hydrolyzed enantiomerically pure ketoacids were cyclized to dihydropyridinones. N-Iodopropylation followed by radical cyclization gave optically active trifluoromethylated indolizidinones stereoselectively.

Regiochemical aspects of intramolecular cycloadditions of nitrones derived from N-(2-alkenyl)-2-pyrrolecarbaldehydes. Competitive entries to pyrrolizidine and indolizidine derivatives

Intramolecular cycloadditions of unsaturated nitrones derived from a series of N-(2-alkenyl)-2-pyrrolecarbaldehydes (2) have been systematically studied. A pronounced substituent effect has been observed as far as the competitive formation of fused- and bridged-ring regioisomers are concerned. Further elaboration of the two kinds of cycloadducts has given pyrrolizidine and indolizidine derivatives, respectively.

Convergent asymmetric synthesis of indolizidines from ( S)-5-(tosylmethyl)-2-pyrrolidinone: synthesis of (−)-δ-coniceine

The enantiomerically pure ( S)-5-(tosylmethyl)-2-pyrrolidinone 2, prepared from commercially available ( S)-pyroglutaminol, is dialkylated at the nitrogen atom and the α-sulfonyl position using several dielectrophiles using sodium hydride as the base to diastereoselectively afford indolizidine derivatives 5 and the less common hexahydropyrrolo[1,2- a]azepin-3-one 6 in moderate to good yield. This domino process has been applied to the synthesis of (−)-δ-coniceine.

The Synthesis of 1‐Methyl‐6,7,8,8a‐tetrahydro‐5H‐indolizin‐3‐one by the Palladium‐Catalyzed Cyclization of N‐Bromoacetyl‐2‐vinylpiperidine

AbstractN‐Bromoacetyl‐2‐vinylpiperidine underwent cyclization to give indolizidine derivative in the presence of a base and a catalytic amount of palladium trifluoroacetate.

ChemInform Abstract: Efficient Synthesis of Pyrrolizidine and Indolizidine Derivatives Using Nickel‐Catalyzed Cyclization of 1,3‐Diene and Aldehyde: Formal Total Synthesis of (‐)‐Elaeokanine C.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: (E)‐5‐Tosyl‐4‐pentenamide: A Vinyl Sulfone for the One‐Pot General Synthesis of Indolizidine Derivatives

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Efficient synthesis of pyrrolizidine and indolizidine derivatives using nickel-catalyzed cyclization of 1,3-diene and aldehyde: Formal total synthesis of (−)-Elaeokanine C

Pyrrolizidine and indolizidine skeletons were successfully constructed by nickel-catalyzed cyclization of 1,3-diene and aldehyde in a chain. A formal total synthesis of an Elaeocarpus alkaloid, (−)-Elaeokanine C, in the naturally occurring form was achieved using this cyclization.

ChemInform Abstract: Synthesis of Indolizidine Derivatives Trifluoromethylated at Bridgehead Position via Acyl Iminium Ion Intermediates Derived from Ring‐Chain Tautomerism of 5,5,5‐Trifluoro‐4‐oxopentanoyl Arylethylamides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

( E)-5-tosyl-4-pentenamide: A vinyl sulfone for the one-pot general synthesis of indolizidine derivatives

( E)-5-tosyl-4-pentenamide ( 3), easily prepared from 4-pentenoic acid by stereoselective iodosulfonylation-dehydroiodination and further amidation with oxalyl chloride and ammonia, reacts with sodium hydride at room temperature in DMF and then with 1,3-dielectrophiles such as 1,3-dihalides and α,β-unsaturated esters to provide stereoselectively differently substituted indolizidines 6.

Synthesis of Indolizidine Derivatives Trifluoromethylated at Bridgehead Position via Acyl Iminium Ion Intermediates Derived from Ring-Chain Tautomerism of 5,5,5-Trifluoro-4-oxopentanoyl Arylethylamides

Synthesis of Indolizidine Derivatives Trifluoromethylated at Bridgehead Position via Acyl Iminium Ion Intermediates Derived from Ring-Chain Tautomerism of 5,5,5-Trifluoro-4-oxopentanoyl Arylethylamides

ChemInform Abstract: Indolizidine Derivatives as Potential Substance P Antagonists.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Electroorganic Syntheses. Part 61. Diastereoselective Cathodic Cyclization of 1‐(4‐ and 1‐(3‐Oxoalkyl)pyridinium Salts to Quinolizidine and Indolizidine Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Indolizidine derivatives as potential substance P antagonists

Two novel indolizidine analogues, ( 7a) and ( 7b), of the substance P antagonist CP 99,994 have been prepared. Possible conformational factors for their low biological activity are discussed.

Diastereoselective Cathodic Cyclization of 1‐(4‐ and 1‐(3‐Oxoalkyl)pyridinium Salts to Quinolizidine and Indolizidine Derivatives

Diastereoselective Cathodic Cyclization of 1‐(4‐ and 1‐(3‐Oxoalkyl)pyridinium Salts to Quinolizidine and Indolizidine Derivatives

ChemInform Abstract: Asymmetric Heck Reaction of Alkenyl Iodides in the Presence of Silver Salts. Catalytic Asymmetric Synthesis of Decalin and Functionalized Indolizidine Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Asymmetric heck reaction of alkenyl iodides in the presence of silver salts. Catalytic asymmetric synthesis of decalin and functionalized indolizidine derivatives

Decalin derivatives 3 (up to 80% ee) and indolizidine derivative 6 (up to 86% ee) have been synthesized by an asymmetric Heck reaction starting with prochiral alkenyl iodides 1 and 4, respectively. The important role of silver salts in the asymmetric Heck reaction is discussed, and the conversion of 6 to δ-coniceine ( 24) is also described.