Transition metal promoted higher-order cycloaddition reactions in organic synthesis

Rigby, James H.

doi:10.1021/ar00035a003

Cited by 150 publications

(44 citation statements)

References 50 publications

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“…Cross peaks were observed between aromatic proton and methine proton at the 7-position, and between methylene proton at the 8-position and methine proton at the 1-position by NOESY experiment. It was found that those relationships are coincided with those report by Rigby [12]. In this way, tricarbonylchromium-coordinated both rings can be independently functionalized by using distinct properties of chromium complexes, and these compounds could be obtained as optically active forms.…”

Section: Resultssupporting

confidence: 84%

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Stereoselective [3+2+2] cycloaddition utilizing optically active binuclear Fischer carbene complexes with alkynes

Kamikawa¹,

Shimizu²,

Matsuzaka³

et al. 2005

Journal of Organometallic Chemistry

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Section: Resultssupporting

confidence: 84%

“…To this end, we examined transition metal promoted higher-order cycloaddition reactions, such as [6p + 4p] and [6p + 2p], utilizing cycloheptatriene chromium tricarbonyl for the synthesis of medium ring size [12]. Binuclear chromium complex 3aa was reacted with methyl acrylate in hexane under irradiation of UV light.…”

Section: Resultsmentioning

confidence: 99%

Stereoselective [3+2+2] cycloaddition utilizing optically active binuclear Fischer carbene complexes with alkynes

Kamikawa¹,

Shimizu²,

Matsuzaka³

et al. 2005

Journal of Organometallic Chemistry

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“…The coordinates of 1 and 2 are shown in Table 2. (7) 0.4481 (6) 49(1) C (6) 0.1465 (7) 1.1488(6) 0.4140 (5) 43(1) C (7) 0.2961 (6) 0.8635(6) -0.0637(5) 34(1) C (8) 0.3437 (8) 0.7207 (7) -0.0662(6) 51(2) C (9) 0.3884(9) 0.6360(6) -0.1820(7) 61(2) C(10) 0.3859 (8) 0.6931 (7) -0.2906(6) 52(2) C(ll) 0.3394 (8) 0.8328 (7) -0.2888(6) 49(1) C ( 12) 0.2952 (7) 0.9197 (7) -0.1740 (6) (7) …”

Section: Resultsmentioning

confidence: 99%

“…2j. [4+2] Cycloadditions may be mediated by high pressure(3), heat, light, sonication (4)(5)(6)(7) or Lewis acids (8)(9)(10)(11)(12)(13)(14)(15)(16).…”

Section: Introductionmentioning

confidence: 99%

Chiral Chelating Systems: Unusual Formation and X-Ray-Structure of Rac-3a(r),4(s),5,9b(s)-Tetrahydro-4-(Pyrid-2-Yl)-3h-Cyclopenta[c]quinoline

Wurst¹,

Buchmeiser²

1999

Heterocyclic Communications

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N-Phenyl-2-(pyrid-2-yl)imine reacts with zinc iodide to give the corresponding diiodo zinc imine complex 1. I reacts with cyclopentadiene (CPD) at 0°C under ultrasound-assisted conditions to yield rac3a(R),4(S),5,9b(S)-tetrahydro-4-(pyrid-2-yl)-3//-cyclopenta[c]quino-line 2 instead of N-phenyl-5-aza-6-pyrid-2-ylnorborn-2-ene. The starting imine reacts with CPD in the same way yet more smoothly using BF, Et,0. With both Lewis-acids, the reaction proceeds regio-and distereoselectively. 1 crystallizes in the centrosymmetric space group Pi, a = 8.127 (1), b = 9.133(1), c = 10.467(1) A,"a = 104.36(1)°, β = 100.35(1)°, γ= 95.93(1)°V = 731.4(1) Ä\ Ζ = 2. 2 crystallizes in the centrosymmetric space group P2,/c. a = 10.559(3)), b = 15.061(2), c = 8.252(1) Α, β = 95.90(2)°, V = 13054(4) A 3 , Ζ = 4.

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“…5 The metal templated [6+4] cycloadditions of tropone with dienes provided an easy access to sesquiterpenoid skeletons having medium-sized rings. 6 Tropone and its derivatives are also known to undergo [4+2] as well as [8+2] addition reactions. Other heteroanalogs of tropone where the oxygen atom is substituted by sulfur or nitrogen, such as thiotropones and cycloheptatrienimines also take part in [8+2] cycloadditions leading to heteroazulene derivatives.…”

Section: Introductionmentioning

confidence: 99%

Cycloaddition Reactions of Heptafulvenes: An Overview

Nair¹,

Anilkumar²

1998

Synlett

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IntroductionFulvenes constitute a unique class of cross conjugated systems. 1 Among the various types of fulvenes, pentafulvene and its analogs have received considerable attention. 2 The cycloaddition profiles of pentafulvenes have been extensively investigated; 3 usually they undergo facile DielsAlder reactions participating both as 4π and 2π addends. 4 Isolated examples where pentafulvenes participate as 6π components in [6+4] additions with dienes are also known. 1bIn comparison to pentafulvenes, the chemistry of heptafulvenes has received only limited attention. Heptafulvene can be considered as an 8π cross-conjugated system analogous to tropone in which the exocyclic oxygen atom is replaced by a methylene group. 1b,c During the past two decades, the cycloaddition reactions of tropone and its derivatives have been studied in detail. Rigby and coworkers exploited their potential in higher-order cycloaddition reactions. 5 The metal templated [6+4] cycloadditions of tropone with dienes provided an easy access to sesquiterpenoid skeletons having medium-sized rings. 6 Tropone and its derivatives are also known to undergo [4+2] as well as [8+2] addition reactions. Other heteroanalogs of tropone where the oxygen atom is substituted by sulfur or nitrogen, such as thiotropones and cycloheptatrienimines also take part in [8+2] cycloadditions leading to heteroazulene derivatives. 7 Higher-order cycloaddition reactions of troponoid systems potentially offer a direct entry into the structural frameworks of several important biologically active natural and unnatural products. 8This review focuses on the different cycloaddition profiles of heptafulvenes with special emphasis on recent advances in the cycloaddition reactions of 2H-cyclohepta[b]furan-2-one. Heptafulvenes as 8π componentsAlthough heptafulvenes can potentially undergo cycloadditions in different modes, the most common pathway involves participation as an 8π component. The pioneering work of Doering and Wiley in 1954 exposed the utility of simple heptafulvene as an 8π synthon. 9 Heptafulvene on treatment with DMAD underwent an [8+2] addition, and a subsequent oxidation of the adduct afforded the azulene derivative 1, rather in poor yield (Scheme 1). Scheme 1Although most of the heptafulvenes are thermally unstable, 8-alkyl and 8-alkoxy heptafulvenes are shown to be excellent 8π partners with electron deficient dienophiles. The [8+2] cycloaddition reactions of 8-methoxy heptafulvene with electron deficient dienophiles such as DMAD, 1,1-dicyano-2-aryl ethylenes, p-benzoquinone, DEAD and 1,1-trifluoromethyl-2,2-dicyano ethylene yielding hydroazulene and heteroazulene derivatives are examples (Scheme 2). 10 Scheme 2 Abstract: Heptafulvenes exhibit multiple reaction profiles in cycloaddition reactions. 8-Alkyl and 8-alkoxy heptafulvenes are shown to be excellent 8π partners with electron deficient dienophiles. Heptafulvene chromium carbonyl complex undergoes [6+4] addition with butadiene. The [4+2] cycloaddition reactions of heptafulvenes yield complex bicyclo syste...

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Transition metal promoted higher-order cycloaddition reactions in organic synthesis

Cited by 150 publications

References 50 publications

Stereoselective [3+2+2] cycloaddition utilizing optically active binuclear Fischer carbene complexes with alkynes

Stereoselective [3+2+2] cycloaddition utilizing optically active binuclear Fischer carbene complexes with alkynes

Chiral Chelating Systems: Unusual Formation and X-Ray-Structure of Rac-3a(r),4(s),5,9b(s)-Tetrahydro-4-(Pyrid-2-Yl)-3h-Cyclopenta[c]quinoline

Cycloaddition Reactions of Heptafulvenes: An Overview

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