Dipolar cycloaddtions of several mesoionic compounds with tert-butylfulvene derivatives; versatile reactions, sterically controlled [4π+ 6π] cycloadditions and a new route to heterocycles isoelectronic with azulene

Katô, Hiroshi; Kobayashi, Tomoshige; Ciobanu, Mona; Iga, Hiroyuki; Akutsu, Akiko; Kakehi, Akikazu

doi:10.1039/cc9960001011

Cited by 19 publications

(6 citation statements)

References 6 publications

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“…Hitherto, only three cyclopenta[c]pyrans without an acceptor substituent have been described: the parent heterocycle 3, its tert-butyl derivative 4 5 and its tert-butyldiphenyl derivative 5. 6 No reactions were performed with 3-5. Being 10p-electron systems, they should be aromatic 7 and thus amenable to electrophilic substitution.…”

mentioning

confidence: 99%

Cyclopenta[c]pyrans from 6-oxo-6H-1,3,4-oxadiazines†

Christl

Bien²,

Bodenschatz³

et al. 1998

Chem. Commun.

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mentioning

confidence: 99%

Cyclopenta[c]pyrans from 6-oxo-6H-1,3,4-oxadiazines†

Christl

Bien²,

Bodenschatz³

et al. 1998

Chem. Commun.

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“…An unexpected route to the cyclopenta[ c ]pyran system was discovered by Kato et al [42, 45] in the cycloaddition of the triphenyloxazolium‐4‐olate 50 with the 2‐ ter t‐butyl‐6‐dimethylaminofulvenes 51 . The bulky substituent of 51 prevented the [4+2] cycloaddition and thus favored the [4+6] cycloaddition.…”

Section: Synthesismentioning

confidence: 99%

Cyclopenta[c]pyrans

Tintas¹,

Bogdan²,

Grosu³

2011

Journal of Heterocyclic Chem

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“…In the early literature, the chemistry of 1,3-dithiolium-4-olates was reported to act as 1,3-dipoles reacting with certain 1,3-dipolarophiles through classical [3 + 2] cycloaddition. For instance, Scheme illustrates the cycloadditions of 1,3-dithiolium-4-olate 1 with alkenes − and alkynes to form bicyclic structures ( 2 and 3 ) bearing a 2,7-dithiabicyclo[2.2.1]heptane motif (Scheme a,b).…”

Section: Introductionmentioning

confidence: 99%

Computational Mechanistic Analysis of Intramolecular Cycloadditions of the 1,3-Dithiolium Cation with Adjacent Alkene and Allene Functional Groups

2018

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In this work, the molecular mechanisms for the intramolecular cycloaddition reactions of the 1,3-dithiolium cation with adjacent alkenyl and allenyl groups were investigated by density functional theory calculations. Transition states for the mechanistic steps were searched, and their connections to corresponding reactive intermediates were validated by the intrinsic reaction coordinate method. Our studies demonstrate that both the alkenyl and allenyl groups can readily react with a neighboring 1,3-dithiolium cation first through a one-step asynchronous [3 + 2] cycloaddition path, with moderate activation energy barriers (ca. 20–30 kcal/mol) to overcome. Subsequent to the intramolecular dithiolium–alkene/allene cycloadditions, the resulting intermediates continue to undergo a series of reactions, including rearrangement, ring opening, and deprotonation to eventually yield the thermodynamically favored products, which carry a fused tricyclic molecular skeleton, 3,8-dihydro-2 H -indeno[2,1- b ]thiophene. Detailed geometric and energetic properties for all of the stationary points (transition states and intermediates) on the reaction potential surfaces have been calculated and examined. Key transition states and reactive intermediates were subjected to quantum theory of atoms in molecules and natural bonding orbital calculations to elucidate their bonding features and the stabilizing effects arising from orbital interactions. Finally, a comparative study using the continuum solvation model based on the charge density was conducted to evaluate the solvent effects on the intramolecular dithiolium–alkene/allene cycloadditions, which are the rate-limiting steps of the overall reactions. The results show that different organic solvents (polar and nonpolar) do not lead to much variations in the heights of activation energy barriers and hence indicate that solvent effects are actually insignificant on the reactions.

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Dipolar cycloaddtions of several mesoionic compounds with tert-butylfulvene derivatives; versatile reactions, sterically controlled [4π+ 6π] cycloadditions and a new route to heterocycles isoelectronic with azulene

Cited by 19 publications

References 6 publications

Cyclopenta[c]pyrans from 6-oxo-6H-1,3,4-oxadiazines†

Cyclopenta[c]pyrans from 6-oxo-6H-1,3,4-oxadiazines†

Cyclopenta[c]pyrans

Computational Mechanistic Analysis of Intramolecular Cycloadditions of the 1,3-Dithiolium Cation with Adjacent Alkene and Allene Functional Groups

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