Synthesis of a Novel Type of 2, 3′‐BIMs via Platinum‐Catalysed Reaction of Indolylallenes with Indoles. Issue 23 (5th March 2018)

• Record Type: Journal Article
• Authors: Cooper, Lisa; Alonso, José Miguel; Eagling, Louise; Newson, Helen; Herath, Sachini; Thomson, Christopher; Lister, Andrew; Howsham, Catherine; Cox, Brian; Muñoz, María Paz
• Is Part Of: Chemistry. Volume 24:Issue 23(2018)
• Page Start: 6105
• Page End: 6114
• Publication Date: 2018-03-05
• Subjects: allenes -- heterocycles -- indoles -- reaction mechanisms -- platinum; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201705417
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Optimisation, scope and mechanism of the platinum‐catalysed addition of indoles to indolylallenes is reported here to give 2, 3′‐BIMs with a novel core structure very relevant for pharmaceutical industry. The reaction is modulated by the electronic properties of the substituents on both indoles, with the 2, 3′‐BIMs favoured when electron donating groups are present. Although simple at first, a complex mechanism has been uncovered that explains the different behaviour of these systems with platinum when compared with other metals (e.g. gold). Detailed labelling studies have shown Pt‐catalysed 6‐ endo‐trig cyclisation of the indollylallene as the first step of the reaction and the involvement of two cyclic vinyl‐platinum intermediates in equilibrium through a platinum carbene, as the key intermediates of the catalytic cycle towards the second nucleophilic attack and formation of the BIMs. Abstract : Closing up : Unique reactivity of indolylallenes under platinum catalysis to form substituted tetrahydropyrido[1, 2a]indoles: an original type of 2, 3′‐BIM.