Insertion of 1-t-butylpropyne into singly tucked-in permethyltitanocene. Synthesis, crystal structure of product and transition-state geometry

Autor: Karel Mach, Katarína Szarka, Jiří Kubišta, Róbert Gyepes, Michal Horáček, Jiří Pinkas
Rok vydání: 2018
Předmět:
Zdroj: Journal of Molecular Structure. 1167:180-186
ISSN: 0022-2860
DOI: 10.1016/j.molstruc.2018.04.071
Popis: The singly tucked-in titanocene [(η5-C5Me5)TiIII{η5:η1-C5Me4(CH2)}] (1) reacted with one equivalent of 1-tert-butylpropyne to yield the propenyl-tethered regioisomer [(η5-C5Me5)Ti(η5:η1-C5Me4CH2C(t-Bu) = κCMe)] (3). The exclusive formation of paramagnetic 3 was proved experimentally and steric reasons were clarified by DFT calculation of transition state which involves both π-systems on the alkyne for bonding interaction with the metal and with sp2 carbon atom of exomethylene group of 1. The obtained compound 3 is by 40 kJ/mol lower in energy than its hypothetical isomer having t-Bu group on Cα of the tether.
Databáze: OpenAIRE