Synthesis of Heterocycles and Carbocycles by Electrophilic Cyclization of Alkynes

Larock, Richard C.

doi:10.1002/3527605487.ch2

Cited by 60 publications

(9 citation statements)

References 115 publications

(140 reference statements)

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“…We have previously reported the generation of various important heterocycles and carbocycles through very efficient electrophilic cyclization chemistry using halogen, sulfur and selenium electrophiles. 1 In particular, we and others have recently found that the iodocyclization of 2-(1-alkynyl)benzamides leads to the formation of the corresponding cyclic imidates, also known in the literature as iminolactones (Scheme 1), where electrophilic attack occurs on oxygen, rather than nitrogen. 2–4 …”

Section: Introductionmentioning

confidence: 93%

Solution-Phase Parallel Synthesis of a Multisubstituted Cyclic Imidate Library

et al. 2013

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The solution-phase parallel synthesis of a diverse 71 member library of multi-substituted cyclic imidates is described. The key intermediates, 3-iodomethylene-containing cyclic imidates, are readily prepared in good to excellent yields by the palladium/copper-catalyzed cross-coupling of various o-iodobenzamides and terminal alkynes, followed by electrophilic cyclization with I2. These cyclic imidates were further functionalized by palladium-catalyzed Suzuki-Miyaura, Sonogashira, carbonylative amidation and Heck chemistry using sublibraries of commercially available building blocks.

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Section: Introductionmentioning

confidence: 93%

Solution-Phase Parallel Synthesis of a Multisubstituted Cyclic Imidate Library

et al. 2013

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“…The electrophilic cyclization of functionally-substituted alkynes has attracted much attention due to its wide utility in the preparation of a range of useful, functionally-substituted heterocycles and carbocycles, 5 such as quinolines, 6 isoxazoles, 7 isoindolin-1-ones, 8 benzo[b]thiophenes, 9 bicyclic β-lactams, 10 indoles, 11 chromones, 12 isochromenes, 13 2-naphthols, 14 benzofurans, 15 cyclic carbonates, 16 pyrroles, 17 furans 18 isocoumarins, 19 α-pyrones, 19 isoquinolines, 20 naphthyridines, 20 polycyclic aromatics, 21 naphthalenes, 22 and furopyridines. 23 Herein, we report an efficient approach to various highly substituted 2(3H)-furanones by the electrophilic cyclization of 3-alkynoate esters and acids.…”

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confidence: 99%

Synthesis of 2(3H)-Furanones via Electrophilic Cyclization

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Larock

2008

J. Org. Chem.

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“…For example, the naturally-occurring compound Spirovibsanin A (I) has been isolated from the plant Viburnum awabuki. 3 The electrophilic cyclization of functionally-substituted alkynes has attracted much attention due to its wide utility in the preparation of a range of useful, functionally-substituted heterocycles and carbocycles, 5 such as quinolines, 6 isoxazoles, 7 isoindolin-1-ones, 8 benzo[b]thiophenes, 9 bicyclic β-lactams, 10 indoles, 11 chromones, 12 isochromenes, 13 2-naphthols, 14 benzofurans, 15 cyclic carbonates, 16 pyrroles, 17 furans 18 isocoumarins, 19 α-pyrones, 19 isoquinolines, 20 naphthyridines, 20 polycyclic aromatics, 21 naphthalenes, 22 and furopyridines. 23 Herein, we report an efficient approach to various highly substituted 2(3H)-furanones by the electrophilic cyclization of 3-alkynoate esters and acids.…”

Section: List Of Abbreviationsmentioning

confidence: 99%

“…General procedure for preparation of the 4-iodo-2(3H)-furanones from alkynoic acids (Table 2). 8, 49.7, 76.7, 127.7, 128.5, 128.6, 130.4, 148.7, 178.9 24.0, 49.5, 109.7, 126.9, 127.9, 128.2, 128.4, 129.4, 129.7, 130.4, 130.5, 154.4, 180.5 Ethyl 2,2-dimethyl-4-(4-methoxyphenyl)but-3-ynoate (5). This compound was prepared according to a literature procedure.…”

Section: Generalmentioning

confidence: 99%

Synthesis of 2(3H)-furanones via electrophilic cyclization

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The electrophilic cyclization of functionally-substituted alkynes is a very promising route to an extraordinary range of medicinally-interesting, functionally-substituted heterocycles and carbocycles. A variety of highly substituted 2(3H)-furanones are readily prepared from 3-alkynoate esters and the corresponding acids via electrophilic cyclization. This highly efficient approach proceeds under mild conditions, tolerates various functional groups, and generally provides 2(3H)-furanones in good to excellent yields. The cyclizations of 3-alkynoate esters and the corresponding acids have been performed using an excess of the electrophile at room temperature using either methylene chloride or acetonitrile as the solvent. Successful electrophiles in this process include I 2 , ICl, and PhSeCl. The iodine functionality introduced into the heterocycle facilitates further elaboration by Pd-catalyzed chemistry. 1 GENERAL INTRODUCTION The electrophilic cyclization of functionally-substituted alkynes has proven to be a very promising route to an extraordinary range of medicinally-interesting, functionallysubstituted heterocycles and carbocycles. Previous work by our group and others has shown that iodine and other electrophiles can be used for the synthesis of benzo[b]furans, benzo[b]thiophenes, indoles, isoquinolines and a number of other heterocycles and carbocycles. This highly efficient approach to heterocycles and carbocycles proceeds under mild reaction conditions, accommodates various functional groups in the starting alkyne, and the iodo-substituted products can be further elaborated by Pd-catalyzed chemistry. Our interest in electrophilic cyclization has led us to further explore the generality of this approach for the synthesis of highly substituted 2(3H)-furanones. We have extensively studied the reaction of 3-alkynoate esters and the corresponding acids with various electrophiles and obtained highly substituted 2(3H)-furanones in fair to excellent yields. Dissertation Organization This thesis is composed of one main chapter. The chapter describes the synthesis of various 2(3H)-furanones from 3-alkynoate esters and the corresponding acids. The cyclization proceeds under relatively mild reaction conditions. Some 3-alkynoate esters give fair to good yields of 2(3H)-furanones, whereas other 3-alkynyl esters with more than one nucleophilic center failed to give the desired 2(3H)-furanones. The unsuccessful 3-alkynoate ester substrates can be easily transformed to the corresponding 3-alkynoic acids. These 3-alkynoic acids cyclize in the presence of various electrophiles to give fair to excellent

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Synthesis of Heterocycles and Carbocycles by Electrophilic Cyclization of Alkynes

Cited by 60 publications

References 115 publications

Solution-Phase Parallel Synthesis of a Multisubstituted Cyclic Imidate Library

Solution-Phase Parallel Synthesis of a Multisubstituted Cyclic Imidate Library

Synthesis of 2(3H)-Furanones via Electrophilic Cyclization

Synthesis of 2(3H)-furanones via electrophilic cyclization

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