[2+2]-cycloadditions of cyclopentyne

Fitjer, Lutz; Kliebisch, U.; Wehle, Detlef; Modaressi, Said

doi:10.1016/s0040-4039(00)87184-1

Cited by 52 publications

(37 citation statements)

References 11 publications

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“…In particular, cyclopentynes, five-membered cyclic alkynes, are highly reactive and short-lived species. Hydrocarbyl cyclopentyne and thiacyclopentyne [4] have been prepared, and the formation was spectroscopically detected [5][6][7] or confirmed by trapping them by subsequent chemical reactions, such as 2 + 2 cycloaddition [8], metal complexation [9][10][11], and so on. However these compounds are so reactive that they have not been isolated in a pure form.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and structure of 1-metallacyclopent-3-yne complexes of group 4 metals

Suzuki

Watanabe

Yoshida

et al. 2006

Journal of Organometallic Chemistry

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Section: Introductionmentioning

confidence: 99%

Synthesis and structure of 1-metallacyclopent-3-yne complexes of group 4 metals

Suzuki

Watanabe

Yoshida

et al. 2006

Journal of Organometallic Chemistry

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“…That 34 has actually been produced was shown by different trapping experiments: for example, in the presence of trans-2-butene the cyclobutene 36 was obtained [34]. In another route cyclopropenone 31 was prepared by photodecomposition of 2,6-diazocyclohexanone in an argon matrix and was decarbonylated on further irradiation at 8 K to 34 [35].…”

Section: Cyclopentyne and Its Derivativesmentioning

confidence: 98%

Angle‐Strained Cycloalkynes

Hopf¹,

Grunenberg²

2009

Strained Hydrocarbons

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IntroductionAccording to the sp-hybridization model, the carbon-carbon triple bond possesses a linear structure, and indeed, many alkynes fulfill this prediction. High level ab initio calculations [1] of isolated alkyne molecules, as well as gas phase electron diffraction experiments [2] reveal their linear minimum structure. On the other hand, given that the C C-R bending force constant becomes intrinsically smaller for substituted alkynes and polyynes, crystal packing effects may lead to deviations from strictly linear geometries [3]. From a dynamic point of view even in the case of acetylene one has to include the -albeit reduced -flexibility of the carboncarbon triple bond in order to describe, for example, the vinylidene acetylene rearrangement (see below) [4]. Further, the linear sp-hybrid picture only holds true for the electronic ground state. Cis-and trans-bent configurations are known in the case of low-lying electronic states [5]. Nevertheless, many alkynes correspond to the prediction of linearity due to the sp-hybrid model, and we have collected a selection of typical examples, reaching from the parent compound acetylene 1 via a few alkyl 2-4 and aryl acetylenes 5-7 to a functionalized acetylene, dimethyl acetylenedicarboxylate 8, in Scheme 7.1, together with the appropriate references [1, 2, 6-11], all dating from the recent literature.The easiest way to distort a triple bond is to incorporate it into a sufficiently small ring structure. The question, of course, is what this ring size is, and from what ring size on the respective cycloalkynes can we isolate compounds, that can be worked with under normal laboratory conditions [12]. Rather than using the nonspecific term 'distorted cycloalkyne' Krebs [12] prefers to speak of 'angle-strained cycloalkynes'. Since it is easier to deform a C C-C arrangement than its more hydrogenated olefinic and saturated analogs, relatively large angle deformations are possible in cycloalkynes without significant changes in energy. Krebs arbitrarily considers all cycloalkynes in which the C C-C angle is deformed by more than 10° as angle-strained [12]. Accepting this definition, the stable cyclononyne (see below) is an angle-strained cycloalkyne, whereas cyclodecyne is not.

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“…Die bisherigen Arbeiten bestätigen, dass Indoline mithilfe von Kobayashis Strategie der Freisetzung des Arins aus einem ortho-Trimethylsilyltriflat durch Behandlung mit einer Fluoridquelle einfach und unter milden Bedingungen hergestellt werden kçnnen (Tabelle 1). [48] Diese Methoden wurden bereits früher besprochen und sollen nicht Gegenstand dieses Kurzaufsatzes sein. Mit dieser Methode untersuchten Garg und Mitarbeiter kürzlich in einer Zusammenarbeit mit Houk den nukleophilen Angriff an Indoline.…”

Section: Nukleophile Reaktionen Von Indolinen Synthese Von Indolactam Vunclassified

“…Konzeptionell andere Zugänge zu Cyclohexinen beruhen auf der Bildung vicinaler Dicarbene oder exocyclischer Vinylidene, die zu Cyclohexinen umlagern. [48] Diese Methoden wurden bereits früher besprochen und sollen nicht Gegenstand dieses Kurzaufsatzes sein. [4,49]…”

Section: Synthese Von Clavilacton Bunclassified

Arine und Cyclohexin in der Naturstoffsynthese

2012

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Erick M. Carreira wurde 1963 in Havanna, Kuba geboren. Er studierte Chemie an der University of Urbana-Champaign (BSc bei Scott Denmark) und promovierte an der Harvard University bei David A. Evans. Es folgte ein Postdoktorat bei Peter Dervan am California Institute of Technology, wo er sich der dortigen Chemiefakultät anschloss. Seit 1998 ist er Professor an der ETH Zürich.Schema 1. Reagentien und Bedingungen: a) AgClO 4 , À10 8C, MS 4 , CH 2 Cl 2 , 86 %, d.r. = 26:1; b) Tf 2 O, iPr 2 NEt, CH 2 Cl 2 , À78 8C, 1 h, 99 %; c) nBuLi, 2-Methoxyfuran, THF, À78 8C, 10 min, 88 %; d) 2-Iod-3-methoxy-5-methylbenzoylchlorid, iPr 2 NEt, DMAP, THF, RT, 2 h, 91 %; e) [(Ph 3 P)PdCl 2 ] (26 Mol-%), NaOAc, DMA, 125 8C, 5 h, 90 %; f) H 2 , Pd/C (10 Mol-%), MeOH, THF, RT, 5 h, 90 %. MS = Molekularsieb, Tf 2 O = Trifluormethansulfonsäureanhydrid, DMAP = N,N-Dimethylaminopyridin. . Angewandte Kurzaufsätze E. M. Carreira und C. M. Gampe Schema 2. Reagentien und Bedingungen: a) TsCl, NEt 3 , DMAP, CH 2 Cl 2 ; b) nBuLi, À78 8C, 3-Lithiofuran, BF 3 OEt 2 , THF, 76 % (2 Stufen); c) KH, BnBr, DMF, 99 %; d) NBS, DMF, 86 %; e) nBuLi, THF, À78 8C, Me 2 Si(Cl)CH=CH 2 , 87 %; f) 9-BBN, THF, H 2 O 2 , NaOH, 96 %; g) 3-Lithiofuran, THF, À78 8C; HCl, EtOH, dann NaCNBH 3 , HCl, 50 8C, 80 %; h) LDA, THF, À78 8C, Me 2 Si(Cl)CH=CH 2 , 70 %; i) 9-BBN, THF, H 2 O 2 , NaOH, 94 %; j) 12, 15, DIAD, PPh 3 , THF, 75 %; k) HF·py, THF, 85 %; l) 14, DIAD, PPh 3 , THF, 85 %; m) nBuLi (3.0 ¾quiv.), Et 2 O, À20 8C, 85 %; n) KOH, DMF/H 2 O; HCl, EtOH, 34 %; o) CAN, MeCN, H 2 O, À15 8C, 74 %; p) IBX, EtOAc, 80 8C; NaClO 2 , NaH 2 PO 4 , 2-Methyl-2-buten, 70 %; q) BBr 3 , CH 2 Cl 2 , À78 8C; MeOH, HCl, 71 %. TsCl = Tosylchlorid, DMF = Me 2 NCHO, 9-BBN = 9-Borabicyclononan, THF = Tetrahydrofuran, DIAD = Diisopropyldiazodicarboxylat, CAN = (NH 4 ) 2 Ce(NO 3 ) 6 , IBX = 2-Iodoxybenzoesäure.

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[2+2]-cycloadditions of cyclopentyne

Cited by 52 publications

References 11 publications

Synthesis and structure of 1-metallacyclopent-3-yne complexes of group 4 metals

Synthesis and structure of 1-metallacyclopent-3-yne complexes of group 4 metals

Angle‐Strained Cycloalkynes

Arine und Cyclohexin in der Naturstoffsynthese

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