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The More Gold—The More Enantioselective: Cyclohydroaminations of γ‐Allenyl Sulfonamides with Mono‐, Bis‐, and Trisphospholane Gold(I) Catalysts
Author(s) -
Rodríguez LaraIsabel,
Roth Torsten,
Lloret Fillol Julio,
Wadepohl Hubert,
Gade Lutz H.
Publication year - 2012
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.201103140
Subject(s) - enantioselective synthesis , catalysis , chemistry , solid state , medicinal chemistry , crystallography , combinatorial chemistry , stereochemistry , polymer chemistry , organic chemistry
A series of chiral mono‐, di‐, and trinuclear gold(I) complexes have been prepared and used as precatalysts in the asymmetric cyclohydroamination of N ‐protected γ‐allenyl sulfonamides. The stereodirecting ligands were mono‐, di‐, and tridentate 2,5‐diphenylphospholanes, which possessed C 1 , C 2 , and C 3 symmetry, respectively, thereby rendering the catalytic sites in the di‐ and trinuclear complexes symmetry equivalent. The C 3 ‐symmetric trinuclear complex displayed the highest activity and enantioselectivity (up to 95 % ee ), whilst its mono‐ and dinuclear counterparts exhibited considerably lower enantioselectivities and activities. A similar trend was observed in a series of mono‐, di‐, and trinuclear 2,5‐dimethylphospholane gold(I) complexes. Aurophilic interactions were established from the solid‐state structures of the trinuclear gold(I) complexes, thereby raising the question as to whether these secondary forces were responsible for the different catalytic behavior observed.