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Highly Fluorinated Tris(indazolyl)borate Silylamido Complexes of the Heavier Alkaline Earth Metals: Synthesis, Characterization, and Efficient Catalytic Intramolecular Hydroamination
Author(s) -
Romero Nuria,
Roşca SorinClaudiu,
Sarazin Yann,
Carpentier JeanFrançois,
Vendier Laure,
MalletLadeira Sonia,
Dinoi Chiara,
Etienne Michel
Publication year - 2015
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.201405454
Subject(s) - homoleptic , hydroamination , chemistry , intramolecular force , medicinal chemistry , agostic interaction , denticity , catalysis , salt metathesis reaction , protonolysis , metathesis , scandium , stereochemistry , crystal structure , crystallography , inorganic chemistry , organic chemistry , metal , polymerization , polymer
Heteroleptic silylamido complexes of the heavier alkaline earth elements calcium and strontium containing the highly fluorinated 3‐phenyl hydrotris(indazolyl)borate {F 12 ‐Tp 4Bo, 3Ph } − ligand have been synthesized by using salt metathesis reactions. The homoleptic precursors [Ae{N(SiMe 3 ) 2 } 2 ] (Ae=Ca, Sr) were treated with [Tl(F 12 ‐Tp 4Bo, 3Ph )] in pentane to form the corresponding heteroleptic complexes [(F 12 ‐Tp 4Bo, 3Ph )Ae{N(SiMe 3 ) 2 }] (Ae=Ca ( 1 ); Sr ( 3 )). Compounds 1 and 3 are inert towards intermolecular redistribution. The molecular structures of 1 and 3 have been determined by using X‐ray diffraction. Compound 3 exhibits a Sr ⋅⋅⋅ MeSi agostic distortion. The synthesis of the homoleptic THF‐free compound [Ca{N(SiMe 2 H) 2 } 2 ] ( 4 ) by transamination reaction between [Ca{N(SiMe 3 ) 2 } 2 ] and HN(SiMe 2 H) 2 is also reported. This precursor constitutes a convenient starting material for the subsequent preparation of the THF‐free complex [(F 12 ‐Tp 4Bo, 3Ph )Ca{N(SiMe 2 H) 2 }] ( 5 ). Compound 5 is stabilized in the solid state by a Ca⋅⋅⋅β‐SiH agostic interaction. Complexes 1 and 3 have been used as precatalysts for the intramolecular hydroamination of 2,2‐dimethylpent‐4‐en‐1‐amine. Compound 1 is highly active, converting completely 200 equivalents of aminoalkene in 16 min with 0.50 mol % catalyst loading at 25 °C.