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Preparation of Tremorine and Gemini Surfactant Precursors with Cationic Ethynyl‐Bridged Digold Catalysts
Author(s) -
Grirrane Abdessamad,
Álvarez Eleuterio,
García Hermenegildo,
Corma Avelino
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201605269
Subject(s) - cationic polymerization , chemistry , catalysis , acetylide , polymer chemistry , phosphine , phenylacetylene , triphenylphosphine , reagent , crystal structure , medicinal chemistry , photochemistry , organic chemistry
Tremorine and precursors of gemini surfactants were synthesised in a one‐pot, three‐step, double‐catalytic A 3 coupling reaction and characterised by structural and spectroscopic methods. The cationic [Au I (L1)]SbF 6 complex is a more active catalyst compared to neutral L2– and L3–Au I bis(trifluoromethanesulfonyl)imidate complexes (L1, L2=Buchwald‐type biaryl phosphane; L3=triphenylphosphine) in promoting the double A 3 coupling of ethynyltrimethylsilane, secondary amines (cyclic, aliphatic, or aromatic) and formaldehyde. The solvent influences the catalytic performance by desilylation of silyl acetylene or deactivation of the catalyst by a halide anion. Acetylide‐bridged cationic digold(I) L1 and L2 complexes were isolated and characterised by means of single‐crystal X‐ray structure analysis and their spectroscopic properties. Iodine in the acetylene reagent deactivates the Au I catalyst by formation of the less active iodido‐bridged cationic digold(I) L1 complex, which was fully characterised by single‐crystal X‐ray crystal structure analysis and spectroscopy. The nature of the phosphine ligand of the gold complexes used as catalyst affects the stability and activity of the formed cationic ethynyl‐bridged Au I 2 –L intermediates, isolation of which lends support to the proposed double A 3 coupling mechanism.