{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.cycloaddition","code":"thing-q898648","url":"https://ver.cy/models/thing/q898648/","name":"cycloaddition","alternateNames":["2+2 photocycloaddition","[4+4] photocycloaddition","(4+3) cycloaddition","[6+4] cycloaddition"],"kind":"thing","status":"research-draft","version":"0.2.0-wave.4","language":"en","classifiers":{"family":"Thing Registry","category":"Activities and processes","entryKind":"thing","plane":"ACT","domain":["ACT.PRC"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A pericyclic chemical reaction in which two or more unsaturated molecules or parts of a molecule combine to form a ring, with a net reduction in bond multiplicity, classified by the number of electrons or atoms involved, such as the [4+2] Diels-Alder reaction, recognised by the 1950 Nobel Prize to Otto Diels and Kurt Alder, 1,3-dipolar cycloadditions used in click chemistry, and forms the registry aliases name including [2+2] and [4+4] photocycloadditions, which require light under Woodward-Hoffmann orbital symmetry rules, (4+3) cycloadditions forming seven-membered rings and [6+4] cycloadditions; the copper-catalysed azide-alkyne cycloaddition contributed to the 2022 Nobel Prize for click chemistry. Some reagents such as azides are hazardous and require trained handling.","purpose":"Let an agent explain cycloadditions, relay classification, mechanisms, orbital symmetry rules and applications from organic chemistry sources at an educational level, describe the named variants, relay general reagent hazards, and distinguish cycloadditions from cyclisation by other mechanisms, electrocyclic reactions, sigmatropic rearrangements and polymerisation.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Ring formation","Concerted mechanisms often","Orbital symmetry control","Stereospecific"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What a cycloaddition is.","layers":[{"id":"definition","name":"Definition","description":"Definition.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"What is a cycloaddition, and how does it differ from other cyclisations, electrocyclic reactions, sigmatropic rearrangements and polymerisation?","kind":"definition"},{"text":"Is the question educational, or a request for hazardous procedures, which this model does not provide?","kind":"boundary"}]}]},{"id":"variants","name":"Variants","description":"Named variants.","findings":[{"id":"variants-finding","name":"Variants","description":"Variants.","questions":[{"text":"What are [2+2] and [4+4] photocycloadditions and (4+3) and [6+4] cycloadditions?","kind":"definition"},{"text":"Which entry fits the specific variant?","kind":"action"}]}]}]},{"id":"theory","name":"Theory","description":"Theory.","layers":[{"id":"orbitals","name":"Orbital symmetry","description":"Woodward-Hoffmann rules.","findings":[{"id":"orbitals-finding","name":"Orbital symmetry","description":"Orbital symmetry.","questions":[{"text":"How do orbital symmetry rules predict allowed thermal and photochemical cycloadditions?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]},{"id":"dielsalder","name":"Diels-Alder","description":"Diels-Alder reaction.","findings":[{"id":"dielsalder-finding","name":"Diels-Alder","description":"Diels-Alder.","questions":[{"text":"Why is the Diels-Alder reaction so useful for building rings?","kind":"provenance"},{"text":"Which sources are cited?","kind":"provenance"}]}]}]},{"id":"applications","name":"Applications","description":"Applications.","layers":[{"id":"click","name":"Click chemistry","description":"Click chemistry.","findings":[{"id":"click-finding","name":"Click chemistry","description":"Click chemistry.","questions":[{"text":"How are azide-alkyne cycloadditions used in click and bioorthogonal chemistry?","kind":"provenance"},{"text":"Which entry fits click chemistry?","kind":"action"}]}]},{"id":"synthesis","name":"Synthesis","description":"Natural product synthesis.","findings":[{"id":"synthesis-finding","name":"Synthesis","description":"Synthesis.","questions":[{"text":"How have cycloadditions enabled total syntheses?","kind":"provenance"},{"text":"Which entry fits total synthesis?","kind":"action"}]}]}]},{"id":"context","name":"Context","description":"Safety and history.","layers":[{"id":"safety","name":"Safety","description":"Reagent hazards.","findings":[{"id":"safety-finding","name":"Safety","description":"Safety.","questions":[{"text":"What general hazards are associated with azides and reactive dienophiles?","kind":"provenance"},{"text":"Which entry fits organic azide?","kind":"action"}]}]},{"id":"nobel","name":"Nobel","description":"Nobel prizes.","findings":[{"id":"nobel-finding","name":"Nobel","description":"Nobel.","questions":[{"text":"Which Nobel Prizes relate to cycloaddition chemistry?","kind":"provenance"},{"text":"Is the information accurate?","kind":"boundary"}]}]}]}]},"agentConduct":{"may":["Explain cycloaddition reactions and their classification, such as the Diels-Alder reaction, from chemistry sources.","Support literature searches and record keeping for a lab running such reactions."],"mustNot":["Provide step-by-step procedures for making controlled, toxic or explosive compounds.","Encourage reactions outside a properly equipped laboratory.","Present predicted stereochemistry or yields as experimental results."],"requiresHuman":["Scaling up reactions or handling hazardous reagents in a lab."]},"ethics":{"considerations":["Synthetic chemistry can serve medicines or harm, so knowledge must be shared responsibly."],"affectedParties":["Laboratory workers","Students"]},"owners":{"steward":"Nobody owns the reaction type; laboratories answer for the work they run.","roles":[],"masterSystems":[]},"relations":[{"target":"Q898403","type":"parent","note":"registry parent class"},{"target":"pericyclic reaction","type":"related","note":"in registry terms"},{"target":"Diels-Alder reaction","type":"related"},{"target":"Woodward-Hoffmann rules","type":"related"},{"target":"electrocyclic reaction","type":"related"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.cycloaddition","Wikidata: Q898648 (https://www.wikidata.org/wiki/Q898648)"]},"properties":{"applicability":"not-applicable","items":["Diels-Alder discovered: 1928 year","Woodward-Hoffmann rules: 1965 year - Nobel 1981 to Hoffmann and Fukui","click chemistry Nobel Prize: 2022 year - Bertozzi, Meldal, Sharpless"]},"recognition":{"applicability":"optional","items":["Ring-forming pericyclic reaction","[2+2] photocycloaddition, [4+4] photocycloaddition, (4+3) cycloaddition, [6+4] cycloaddition, Diels-Alder reaction","Other cyclisations use different mechanisms; electrocyclic reactions close one conjugated system; sigmatropic rearrangements move bonds; polymerisation forms chains","Not a physical object; drawn as reaction schemes forming rings."]},"capabilities":{"applicability":"required","items":["explain classification and mechanisms","relay Woodward-Hoffmann rules","describe named variants","relay applications and hazards in general terms"]},"hazards":{"applicability":"required","items":["Handling explosive azides","Providing hazardous procedures","Confusing thermal and photochemical rules"]},"interfaces":{"applicability":"required","items":["Laboratory chemical safety rules","Hazard classification for azides and dienophiles"]},"context":{"applicability":"required","items":["Forming rings in chemical synthesis.","[4+2] cycloadditions","[2+2] cycloadditions","1,3-dipolar cycloadditions","higher-order cycloadditions","photochemical cycloadditions"]}},"sources":[{"title":"Wikidata item Q898648: cycloaddition","url":"https://www.wikidata.org/wiki/Q898648","note":"identity and sense of the item"},{"title":"Wikipedia: Cycloaddition","url":"https://en.wikipedia.org/wiki/Cycloaddition","note":"general description of the item"}],"openQuestions":["Should photocycloadditions be a separate entry?","How should organic chemistry references be linked?","Should click chemistry be linked separately?"],"resources":{"spec":"/models/things/publications/thing-q898648/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q898648/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-14T00:01:21Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"interaction.properties":"Plane ACT: no invented physical properties."},"score":1.0}}