OnlySó theo enlace pi de C-2 toe C-3 pi-bonddo ofindol indolepode is capable ofexperimentar [[cycloadditionreacción reactionde cicloadición|reaccións de cicloadición]]s. IntramolecularAs variantsvariantes areintramoleculares oftenson higher-yieldinga thanmiúdo intermolecularde cycloadditionsmaior rendemento que as cicloadicións intermoleculares. ForPor exampleexemplo, Padwa ''et al.''<ref name="lynch2002">{{cite journal|author = Lynch, S. M. ; Bur, S. K.; Padwa, A.|journal = [[Org. Lett.]]|doi = 10.1021/ol027024q|pmid = 12489950|title = Intramolecular Amidofuran Cycloadditions across an Indole π-Bond: An Efficient Approach to the ''Aspidosperma'' and ''Strychnos'' ''ABCE'' Core|year = 2002|volume = 4|issue = 26|page = 4643}}</ref> havedesenvolveron developed thisesta [[reacción de Diels-Alder reaction]] topara formformar advancedintermediarios de [[strychnineestricnina]] intermediatesavanzados. InNeste this casecaso, theo 2-aminofuranaminofurano isé theo [[dienedieno]], whereasmentres theque indoleo isindol theé o [[dienophiledienófilo]]. IndolesOs alsoindois undergotamén intramolecularsofren cicloadicións intramoleculares [2+3] ande [2+2] cycloadditions.
:[[FileFicheiro:Indole Cycloaddition Padwa.png|250px|Exampleminiatura|Exemplo ofdunha acicloadición cycloadditionde of indoleindol.]]
DespiteMalia mediocreos yieldsrendementos mediocres que se obteñen, intermolecularas cycloadditionscicloadicións ofintermoleculares indolede derivativesderivados do haveindol beenestán wellben documenteddocumentadas.<ref name="cox1995">{{Cite doi|10.1021/cr00038a004}}</ref><ref>{{cite journal | author = Gremmen, C.; Willemse, B.; Wanner, M. J.; Koomen, G.-J. | journal = [[Org. Lett.]] | volume = 2 | year = 2000 | pages = 1955–1958 | doi = 10.1021/ol006034t | title = Enantiopure Tetrahydro-β-carbolines via Pictet-Spengler Reactions with N-Sulfinyl Tryptamines | issue = 13}}</ref><ref>a)'' The intermolecular Pictet-Spengler condensation with chiral carbonyl derivatives in the stereoselective syntheses of optically-active isoquinoline and indole alkaloids'' Enrique L. Larghi, Marcela Amongero, Andrea B. J. Bracca, and Teodoro S. Kaufman [[Arkivoc]] (RL-1554K) pp 98-153 '''2005''' ([http://arkat-usa.org/ark/journal/2005/I12_Lederkremer/1554/1554.asp Online Review]); b) Teodoro S. Kaufman “Synthesis of Optically-Active Isoquinoline and Indole Alkaloids Employing the Pictet-Spengler Condensation with Removable Chiral Auxiliaries Bound to Nitrogen”. in “New Methods for the Asymmetric Synthesis of Nitrogen Heterocycles”; Ed.: J. L. Vicario. ISBN 81-7736-278-X. Research SignPost, Trivandrum, India. 2005. Chapter 4, pp. 99-147.</ref> Un exemplo Oneé examplea is[[reacción thede [[Pictet-Spengler reaction]] betweenentre derivados do [[tryptophantriptófano]] derivatives ande [[aldehydesaldehido]]s.<ref>{{cite journal | author = Bonnet, D.; Ganesan, A. | journal = [[J. Comb. Chem.]] | year = 2002 | volume = 4 | issue = 6 | pages = 546–548 | title = Solid-Phase Synthesis of Tetrahydro-β-carbolinehydantoins via the N-Acyliminium Pictet-Spengler Reaction and Cyclative Cleavage | doi = 10.1021/cc020026h }}</ref> TheA reacción de Pictet-Spengler reactionde ofderivados indoledo derivativesindol, suchcomo aso tryptophantriptófano, leadsorixina tocomo aprodutos mixtureunha ofmestura de [[diastereomersdiastereómero]] as productss. A Theformación formationde ofmúltiples multipleprodutos productsreduce reduces theo [[chemicalrendemento yieldquímico]] of thedo desiredproduto productdesexado.
