A Comprehensive History of Arynes in Natural Product Total Synthesis

Tadross, Pamela M.; Stoltz, Brian M.

doi:10.1021/cr200478h

Cited by 789 publications

(302 citation statements)

References 183 publications

Supporting

Mentioning

297

Contrasting

Unclassified

Order By: Relevance

“…Arynes are highly reactive intermediates useful for preparing diverse aromatic compounds [1][2][3][4][5][6][7][8]. Novel transformations of arynes have been achieved and applied to the synthesis of a wide range of complex aromatic compounds.…”

Section: Introductionmentioning

confidence: 99%

An Alternative Method for Generating Arynes from ortho-Silylaryl Triflates: Activation by Cesium Carbonate in the Presence of a Crown Ether

et al. 2015

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

An Alternative Method for Generating Arynes from ortho-Silylaryl Triflates: Activation by Cesium Carbonate in the Presence of a Crown Ether

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Silyltriflates have served as valuable masked equivalents of other classes of strained or unstable alkynes,s uch as arynes, [12] heteroarynes, [13] cyclic alkynes, [14] and allenes. [15] Revealing the appropriate alkyne via elimination in the presence of ar eaction partner often gives the desired products in high yields.H aving imagined that as imilar strategy would be possible using 7,w ew ere pleased to find that the addition of 3.0 equivalents of nitrone 9 resulted in the rapid formation of the desired 4-nitro-4-isoxazoline 10 in ah igh yield (Table 1, entry 1).…”

mentioning

confidence: 99%

Synthesis and Utilization of Nitroalkyne Equivalents in Batch and Continuous Flow

Morse

Jamison

2017

Angewandte Chemie

View full text Add to dashboard Cite

We report amethod for overcoming the low stability of nitroalkynes through the development of nitrated vinyl silyltriflate equivalents.B ecause of their instability,n itroalkynes have only rarely been utilized in synthesis.The reactivity of these silyltriflates,whichare prepared in situ, is exemplified by dipolar cycloaddition reactions with nitrones to give highly substituted 4-nitro-4-isoxazolines in high yields.This approach has proven general for several different alkyla nd aryl substituted alkynes.I no rder to minimizet he accumulation of potentially hazardous reaction intermediates,w eh ave also developed ac ontinuous flow variant of this method that is capable of carrying out the entire reaction sequence in agood yield and ashort residence time.

show abstract

“…The most direct method for synthesizing 1-substituted benzocyclobutenes is by [2+2] cycloaddition of benzyne 17 with an alkene, especially electron-rich alkenes such as vinyl ethers and vinyl acetate. 18,19 Due to the many routes for converting 4-bromobenzocyclobutene into vinylbenzocyclobutene, 7,9,14,15 we considered the three possible starting materials shown in Scheme 2 for synthesizing 4-bromo-1-ethoxybenzocyclobutene via a benzyne intermediate.…”

mentioning

confidence: 99%

Synthesis of a Polymerizable Benzocyclobutene that Undergoes Ring-Opening Isomerization at Reduced Temperature

Pugh

Baker

Storms

2013

Synlett

View full text Add to dashboard Cite

1-Ethoxyvinylbenzocyclobutene is a substituted benzocyclobutene that undergoes radical polymerization to produce polymers that can be crosslinked at 100-150°C. The 4-and 5-vinyl isomers are synthesized in a 1:4 ratio via a halogenated benzyne intermediate produced from anthranilic acid, followed by cycloaddition with ethyl vinyl ether and replacement of the halogen atom with a vinyl group.Key words: benzocyclobutene, cycloaddition, ring-opening isomerization, Kumada coupling, benzyne Bicyclo[4.2.0]octa-1,3,5-triene, or benzocyclobutene (BCB), 1,2 has been widely used in polymer science based on the ring-opening ability of the strained cyclobutene ring. 3It is stable at room temperature, but undergoes an electrocyclic rearrangement at elevated temperature (>200°C) to the highly reactive o-quinodimethane. The o-quinodimethane undergoes Diels-Alder reactions, and in the absence of an external dienophile, generates 1,2,5,6-dibenzocyclooctane (~25%) and higher oligomers (~75%) (Scheme 1). 4,5Since the thermally unstable spirodimer does not generate any 1,2,5,6-dibenzocyclooctane upon heating, it apparently forms by a different mechanism than the oligomers. 5 This thermal activation and the lack of condensation byproducts makes benzocyclobutene chemistry especially attractive for crosslinking 6 and for polymer-forming reactions 3 by a step (condensation-like) mechanism. Benzocyclobutene-containing vinyl monomers have also been polymerized by chain mechanisms. 7-10Although the high temperature of the ring-opening isomerization reaction is useful for applications such as the crosslinking of engineering polymers, which are synthesized at elevated temperatures, it also limits the use of benzocyclobutene in other applications, such as those involving temperature-sensitive materials. For example, it would be difficult to exploit the benzocyclobutene crosslinking reaction to create nanostructured flexible films by field-assisted roll-to-roll processing if the glass transition temperature of the substrate polymer film and/or the available thermal field are significantly less than 200°C. We are particularly interested in developing nanostructured flexible films using block copolymers that can be aligned and crosslinked at more reasonable temperatures than those used to crosslink benzocyclobutene. Scheme 1 Electrocyclic ring-opening of benzocyclobutene and its subsequent [4+2] cycloaddition with another o-quinodimethane 4The ring-opening isomerization temperature of benzocyclobutenes can be lowered by introducing both electrondonating (raises the ground state energy) and electronwithdrawing (lowers the transition state energy) substituents onto the cyclobutene ring. 5For example, 1-methoxybenzocyclobutene isomerizes at ≥110°C, 11 and the cyclobutene rings of poly(1-benzocyclobutenyl vinyl ether) isomerize at ≥60°C. 12(The temperature range over which the exothermic isomerization transitions occur is usually broad.) Block copolymers with controlled chain lengths are prepared by chain polymerizations, such as living ...

show abstract

A Comprehensive History of Arynes in Natural Product Total Synthesis

Abstract: Scheme 1. Methods for the Generation of Benzyne (1) Scheme 2. Representative Reactions of Benzyne (1) 6 Review pubs.acs.org/CR

Cited by 789 publications

References 183 publications

An Alternative Method for Generating Arynes from ortho-Silylaryl Triflates: Activation by Cesium Carbonate in the Presence of a Crown Ether

An Alternative Method for Generating Arynes from ortho-Silylaryl Triflates: Activation by Cesium Carbonate in the Presence of a Crown Ether

Synthesis and Utilization of Nitroalkyne Equivalents in Batch and Continuous Flow

Synthesis of a Polymerizable Benzocyclobutene that Undergoes Ring-Opening Isomerization at Reduced Temperature

Contact Info

Product

Resources

About