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Magnesiation of N ‐Methyl‐1, 3‐propylenediaminoboryl Ferrocene
Author(s) -
Reichert Adelina,
Schmidt Jurema,
Bolte Michael,
Wagner Matthias,
Lerner HansWolfram
Publication year - 2013
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201300029
Subject(s) - ferrocene , metalation , chemistry , tetrahydropyran , medicinal chemistry , yield (engineering) , homoleptic , derivative (finance) , tetrahydrofuran , organic chemistry , ring (chemistry) , electrochemistry , materials science , electrode , solvent , economics , financial economics , metal , metallurgy
N ‐methyl‐1, 3‐propylenediaminoboryl ferrocene ( 1 ‐H) was obtained by a three‐step synthesis: i) At first ferrocene was reacted with BBr 3 to give dibromoboryl ferrocene (FcBBr 2 ). ii) In a second step FcBBr 2 was transformed into FcB(OMe) 2 by treatment of FcBBr 2 with Me 3 SiOMe. iii) Finally reaction of FcB(OMe) 2 with H 2 NCH 2 CH 2 CH 2 NMeH yielded the boryl ferrocene 1 ‐H. In addition we examined the metalation of 1 ‐H with magnesium 2, 2, 6, 6‐tetramethylpiperidide (TMP) and mixtures of Li(TMP)/Mg(TMP) 2 . The reaction of 1 ‐H with 0.5 equivalent of Mg(TMP) 2 yielded quantitatively the homoleptic complex Mg[ 1 ] 2 whereas metalation of 1 ‐H with 1.5 and 2 equivalents of Mg(TMP) 2 gave product mixtures. However, N , N '‐dimethyl‐1, 3‐propylenediaminoboryl ferrocene ( 1 ‐Me) and the ortho‐ methylated derivatives 2 ‐Me and 3 ‐Me ( 3 ‐Me bears additionally one Me group in 1′‐postion) could be identified after derivatization with Me 2 SO 4 . The metalated ferrocene derivative (Li 2 (THP) 2 Mg 3 (TMP) 2 [ 3 ] 2 ) which is bearing one Li and one Mg atom in the ortho ‐position and a further two Mg atoms in N ‐ and 1′‐positions, was formed in good yield by treatment of 1 ‐H with an excess of a 1:2 mixture of Li(TMP) and Mg(TMP) 2 in tetrahydropyran (THP). Single crystals of the racemic complex Li 2 (THP) 2 Mg 3 (TMP) 2 [ 3 ] 2 were available by gas‐phase diffusion of hexane into a concentrated THP solution at ambient temperature (space group C 2/ c ). The crystal structure of Li 2 (THP) 2 Mg 3 (TMP) 2 [ 3 ] 2 displays a racemic dimer of the R p ‐ and the S p ‐enantiomer.