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Hydroboration, Cyanosilylation, and Sequential Cyanosilylation and Hydroboration of Carbonyl Compounds in the Presence of a Ti IV Amido Complex as an Efficient Catalyst
Author(s) -
Harinath Adimulam,
Bhattcharjee Jayeeta,
Gorantla Koteswar Rao,
Mallik Bhabani S.,
Panda Tarun K.
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800547
Subject(s) - hydroboration , chemistry , catalysis , trimethylsilyl cyanide , medicinal chemistry , trimethylsilyl , ligand (biochemistry) , organic chemistry , biochemistry , receptor
Catalytic hydroboration and cyanosilylation of a wide range of aldehydes and ketones, with pinacolborane (4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolane) and trimethylsilyl cyanide, respectively, in the presence of titanium(IV) complexes [κ 2 ‐{(C 5 H 4 N)CH 2 N‐P(=Se)Ph 2 }Ti(NMe 2 ) 3 ] ( 1 ) and [{κ 2 ‐(C 6 H 4 F)NP(=Se)Ph 2 }Ti(NMe 2 ) 3 ] ( 2 ) are reported. The catalytic hydroboration and cyanosilylation processes are high‐yielding and general, and result in efficient conversion of carbonyl compounds into the corresponding products under mild conditions. Titanium catalyst 1 exhibits high tolerance toward several functional groups. First‐order kinetics with respect to the catalyst and each of the substrates were observed for the titanium‐catalyzed hydroboration of carbonyl compounds. First‐principles calculations were performed to explore the catalytic hydroboration reaction mechanism. In addition, a combination of both reactions and sequential cyanosilylation/hydroboration is reported. Ti IV complexes 1 and 2 were prepared by aminolysis of [Ti(NMe 2 ) 4 ] with protic ligands [(C 5 H 4 N)CH 2 NHP(=Se)Ph 2 ] ( L 1 H ) and [(C 6 H 4 F)NHP(=Se)Ph 2 ] ( L 2 H ), respectively. The third titanium complex [κ 4 ‐{Ph 2 P(=Se)NCH(C 5 H 4 N)CH(C 5 H 4 N)P(=Se)Ph 2 }‐Ti(NMe 2 ) 2 ] ( 3 ) was obtained from the reaction between [Ti(NMe 2 ) 4 ] and ligand L 1 H in a 1:2 molar ratio at room temperature. The molecular structures of complexes 1 and 3 in the solid state are reported.