Subtopic Deep Dive
Regioselectivity in Unsymmetrical Aryne Reactions
Research Guide
What is Regioselectivity in Unsymmetrical Aryne Reactions?
Regioselectivity in unsymmetrical aryne reactions refers to the electronic and steric control determining nucleophile addition sites to 3-substituted arynes, guided by directing groups, distortion energies, and computational models.
Unsymmetrical arynes, such as 3-silylarynes and indolynes, exhibit regioselectivities influenced by aryne distortion and steric effects (Bronner et al., 2012, 153 citations; Cheong et al., 2010, 243 citations). Computational studies using distortion/interaction-activation strain models predict addition preferences (Bickelhaupt and Houk, 2017, 1561 citations). Over 10 key papers from 2008-2020 document experimental syntheses and fluoroalkylation regioselectivities (Ni et al., 2008, 155 citations).
Why It Matters
Precise regioselectivity enables synthesis of ortho- or meta-substituted arenes from abundant precursors, critical for pharmaceuticals like indolactam V (Bronner et al., 2011, 158 citations). Aryne distortions control nucleophile additions in 3-silylarynes, competing with steric bulk to favor meta products with large nucleophiles (Bronner et al., 2012, 153 citations). Fluorinated sulfones add regioselectively to arynes, probing hard/soft carbanion nature for bioactive fluorinated motifs (Ni et al., 2008, 155 citations). Computational models by Houk and Garg predict indolyne selectivities, accelerating drug scaffold design (Cheong et al., 2010, 243 citations; Im et al., 2010, 239 citations).
Key Research Challenges
Predicting Distortion Energies
Aryne bending distorts transition states, favoring ortho addition in 4,5-indolynes but not 5,6-indolynes (Cheong et al., 2010, 243 citations). Density functional theory computations quantify these energies but require validation across substituents. Steric competition in 3-silylarynes complicates predictions (Bronner et al., 2012, 153 citations).
Steric vs Electronic Control
Large nucleophiles favor meta addition to 3-silylarynes despite electronic distortion biases (Bronner et al., 2012, 153 citations). Directing groups and fluoride effects modulate regioselectivity but lack general rules. Computational models struggle with bulky additives (Bickelhaupt and Houk, 2017, 1561 citations).
Generating Unsymmetrical Arynes
Unsymmetrical diaryliodonium salts enable C-H deprotonative aryne formation, but regioselectivity varies with mesityl leaving groups (Stuart, 2016, 102 citations). Precursor synthesis limits access to 3-substituted arynes for pharmaceuticals. Multifunctionalization via 1,2-benzdiyne adds complexity (He et al., 2020, 124 citations).
Essential Papers
Analyzing Reaction Rates with the Distortion/Interaction‐Activation Strain Model
F. Matthias Bickelhaupt, K. N. Houk · 2017 · Angewandte Chemie International Edition · 1.6K citations
Abstract The activation strain or distortion/interaction model is a tool to analyze activation barriers that determine reaction rates. For bimolecular reactions, the activation energies are the sum...
Employing Arynes in Diels–Alder Reactions and Transition-Metal-Free Multicomponent Coupling and Arylation Reactions
Sachin Suresh Bhojgude, Anup Bhunia, Akkattu T. Biju · 2016 · Accounts of Chemical Research · 296 citations
Arynes are highly reactive intermediates having several applications in organic synthesis for the construction of various ortho-disubstituted arenes. Traditionally, arynes are generated in solution...
Uncovering the Neglected Similarities of Arynes and Donor–Acceptor Cyclopropanes
Daniel B. Werz, Akkattu T. Biju · 2019 · Angewandte Chemie International Edition · 276 citations
Abstract Arynes and donor–acceptor (D–A) cyclopropanes are two classes of strained systems having the potential for numerous applications in organic synthesis. The last two decades have witnessed a...
Indolyne and Aryne Distortions and Nucleophilic Regioselectivites
Paul H.-Y. Cheong, Robert S. Paton, Sarah M. Bronner et al. · 2010 · Journal of the American Chemical Society · 243 citations
Density functional theory computations reproduce the surprisingly high regioselectivities in nucleophilic additions and cycloadditions to 4,5-indolynes and the low regioselectivities in the reactio...
Indolyne Experimental and Computational Studies: Synthetic Applications and Origins of Selectivities of Nucleophilic Additions
G-Yoon Jamie Im, Sarah M. Bronner, Adam E. Goetz et al. · 2010 · Journal of the American Chemical Society · 239 citations
Efficient syntheses of 4,5-, 5,6-, and 6,7-indolyne precursors beginning from commercially available hydroxyindole derivatives are reported. The synthetic routes are versatile and allow access to i...
Overturning Indolyne Regioselectivities and Synthesis of Indolactam V
Sarah M. Bronner, Adam E. Goetz, Neil K. Garg · 2011 · Journal of the American Chemical Society · 158 citations
We report the design and synthesis of an indolyne that displays a reversal in regioselectivity, in both nucleophilic addition and cycloaddition reactions, compared to typical 4,5-indolynes. Our app...
Nucleophilic Fluoroalkylation of α,β-Enones, Arynes, and Activated Alkynes with Fluorinated Sulfones: Probing the Hard/Soft Nature of Fluorinated Carbanions
Chuanfa Ni, Laijun Zhang, Jinbo Hu · 2008 · The Journal of Organic Chemistry · 155 citations
We have successfully accomplished the nucleophilic fluoroalkylation of alpha,beta-enones, arynes, and activated alkynes with fluorinated sulfones. It was found that for acylic alpha,beta-enones, al...
Reading Guide
Foundational Papers
Start with Cheong et al. (2010, 243 citations) for distortion theory in indolynes and arynes; follow with Im et al. (2010, 239 citations) for experimental validations and syntheses; Bronner et al. (2012, 153 citations) details steric competition in 3-silylarynes.
Recent Advances
He et al. (2020, 124 citations) on multifunctional arynes; Werz and Biju (2019, 276 citations) comparing arynes to cyclopropanes; Stuart (2016, 102 citations) on diaryliodonium synthons.
Core Methods
Distortion/interaction-activation strain model (Bickelhaupt and Houk, 2017); DFT transition state analysis (Cheong et al., 2010); nucleophilic additions with fluorosulfones (Ni et al., 2008); C-H deprotonation via iodonium salts (Stuart, 2016).
How PapersFlow Helps You Research Regioselectivity in Unsymmetrical Aryne Reactions
Discover & Search
Research Agent uses citationGraph on Cheong et al. (2010, 243 citations) to map Houk-Garg collaborations on indolyne distortions, then findSimilarPapers reveals 3-silylaryne extensions (Bronner et al., 2012). exaSearch queries 'regioselectivity 3-substituted arynes steric distortion' for 50+ OpenAlex papers beyond the list.
Analyze & Verify
Analysis Agent runs readPaperContent on Bronner et al. (2012) to extract regioselectivity ratios, then verifyResponse with CoVe cross-checks computed vs experimental meta/ortho yields. runPythonAnalysis plots distortion energies from Bickelhaupt-Houk (2017) data using NumPy, graded by GRADE for statistical reliability.
Synthesize & Write
Synthesis Agent detects gaps in steric control for bulky nucleophiles across Bronner (2012) and Cheong (2010), flagging contradictions in indolyne predictions. Writing Agent applies latexEditText to regioselectivity schemes, latexSyncCitations for Houk-Garg papers, and latexCompile for publication-ready reviews; exportMermaid diagrams aryne distortion pathways.
Use Cases
"Analyze regioselectivity data from 3-silylarynes with Python plotting"
Research Agent → searchPapers('3-silylarynes Bronner') → Analysis Agent → readPaperContent → runPythonAnalysis(NumPy pandas matplotlib on yield ratios) → matplotlib plot of ortho/meta trends saved as PNG.
"Write LaTeX review on indolyne regioselectivity reversals"
Synthesis Agent → gap detection('indolyne regioselectivity Garg') → Writing Agent → latexEditText(structured abstract) → latexSyncCitations(Cheong 2010, Bronner 2011) → latexCompile → PDF with aryne schemes.
"Find GitHub code for aryne distortion simulations"
Research Agent → searchPapers('distortion interaction aryne Houk') → Code Discovery → paperExtractUrls(Bickelhaupt 2017) → paperFindGithubRepo → githubRepoInspect → Python scripts for activation strain models.
Automated Workflows
Deep Research workflow scans 50+ aryne papers via citationGraph from Cheong et al. (2010), generating structured reports on regioselectivity trends with GRADE grading. DeepScan applies 7-step CoVe to verify Bronner et al. (2012) steric claims against computations. Theorizer builds models linking aryne distortion to nucleophile size from Houk-Garg datasets.
Frequently Asked Questions
What defines regioselectivity in unsymmetrical arynes?
Nucleophile addition prefers sites dictated by aryne distortion energies and steric bulk, with ortho selectivity in small nucleophiles and meta in large ones (Bronner et al., 2012; Cheong et al., 2010).
What methods control aryne regioselectivity?
Distortion/interaction models compute barriers (Bickelhaupt and Houk, 2017); directing groups, silyl substituents, and fluoride effects experimentally tune addition (Stuart, 2016; Ni et al., 2008).
What are key papers on this topic?
Foundational: Cheong et al. (2010, 243 citations) on indolyne distortions; Im et al. (2010, 239 citations) on syntheses. Recent: Bronner et al. (2012, 153 citations) on 3-silylarynes; He et al. (2020, 124 citations) on multifunctionalization.
What open problems remain?
Generalizing steric-electronic balance for diverse nucleophiles and substituents; scalable generation of multifunctional unsymmetrical arynes; predictive models beyond DFT for pharmaceuticals (Bronner et al., 2012; He et al., 2020).
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