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Oxygen Capture by Lithiated Organozinc Reagents Containing Aromatic 2‐Pyridylamide Ligands
Author(s) -
Davies Robert P.,
Linton David J.,
Schooler Paul,
Snaith Ronald,
Wheatley Andrew E. H.
Publication year - 2001
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 - 10.1002/1521-3765(20010903)7:17<3696::aid-chem3696>3.0.co;2-o
Subject(s) - chemistry , zincate , steric effects , octahedron , medicinal chemistry , reagent , dimer , oxygen , crystallography , amine gas treating , oxygen atom , lithium (medication) , stereochemistry , zinc , crystal structure , molecule , organic chemistry , medicine , endocrinology
The sequential reaction of ZnMe 2 with a 2‐pyridylamine (HN(2‐C 5 H 4 N)R, R=Ph: 1 ; 3,5‐Xy (=3,5‐xylyl): 2 ; 2,6‐Xy: 3 ; Bz (=benzyl): 4 ; Me: 5 ), t BuLi and thereafter with oxygen affords various lithium zincate species, the solid‐state structures of which reveal a diversity of oxo‐capture modes. Amine 1 reacts to give both dimeric THF⋅[Li(Me)OZn{N(2‐C 5 H 4 N)Ph} 2 ] ( 6 ), wherein oxygen has inserted into the Zn−C bond of a {MeZn[N(2‐C 5 H 4 N)Ph] 2 } − ion, and the trigonal Li 2 Zn complex, bis (O t Bu)‐capped (THF⋅Li) 2 [{( μ 3 ‐O )t Bu} 2 Zn{N(2‐C 5 H 4 N)Ph} 2 ] ( 7 ). The structural analogue of 6 ( 8 ) results from the employment of 2 , while the use of more sterically congested 3 yields a pseudo‐cubane dimer [{THF⋅[Li( t Bu)OZn(O t Bu)Me]} 2 ] ( 9 ) notable for the retention of labile Zn−C(Me). Amines 4 and 5 afford the oxo‐encapsulation products [( μ 4 ‐O)Zn 4 {(2‐C 5 H 4 N)NBz} 6 ] ( 10 b ), and [ t Bu( μ 3 ‐O)Li 3 ( μ 6 ‐O)Zn 3 {(2‐C 5 H 4 N)NMe} 6 ] ( 11 ), respectively, with concomitant oxo‐insertion into a Li−C interaction resulting in capping of the fac ‐isomeric ( μ 6 ‐O)M 3 M′ 3 distorted octahedral core of the latter complex by a tert ‐butoxide group.