Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 5332-5341 |
| Number of pages | 10 |
| Journal | Dalton Transactions |
| Volume | 40 |
| Issue number | 19 |
| DOIs | |
| Publication status | Published - 31 Mar 2011 |
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Keywords
- sparteine-mediated deprotonation
- inverse crown-ether
- enantioselective lithiation-substitution
- carbon bond formations
- cation-pi interactions
- asymmetric-synthesis
- crystal-structures
- conjugate additions
- amide chemistry
- n-boc-pyrrolidine
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Synthesis and structural chemistry of alkali metal tris(HMDS) magnesiates containing chiral diamine donor ligands. / Garcia-Alvarez, Pablo; Kennedy, Alan R.; O'Hara, Charles T.; Reilly, Kieran; Robertson, Gemma M.
In: Dalton Transactions, Vol. 40, No. 19, 31.03.2011, p. 5332-5341.Research output: Contribution to journal › Article
TY - JOUR
T1 - Synthesis and structural chemistry of alkali metal tris(HMDS) magnesiates containing chiral diamine donor ligands
AU - Garcia-Alvarez, Pablo
AU - Kennedy, Alan R.
AU - O'Hara, Charles T.
AU - Reilly, Kieran
AU - Robertson, Gemma M.
PY - 2011/3/31
Y1 - 2011/3/31
N2 - Six alkali metal tris(HMDS) magnesiate complexes (HMDS, 1,1,1,3,3,3,-hexamethyldisilazide) containing chiral diamine ligands have been prepared and characterised in both the solid- and solution-state. Four of the complexes have a solvent-separated ion pair composition of the form [{M∙(chiral diamine)2}+{Mg(HMDS)3}−] [M = Li for 1 and 3, Na for 2 and 4; chiral diamine = (−)-sparteine for 1 and 2, (R,R)-TMCDA for 3 and 4, (where (R,R)-TMCDA is N,N,N′,N'-(1R,2R)-tetramethylcyclohexane-1,2-diamine)] and two have a contacted ion pair composition of the form [{K∙chiral diamine}+{Mg(HMDS)3}−]n [chiral diamine = (−)-sparteine for 5 and (R,R)-TMCDA for 6]. In the solid-state, complexes 1–4 are essentially isostructural, with the lithium or sodium cation sequestered by the respective chiral diamine and the previously reported anion consisting of three HMDS ligands coordinated to a magnesium centre. As such, complexes 1–4 are the first structurally characterised complexes in which the alkali metal is sequestered by two molecules of either of the chiral diamines (–)-sparteine (1 and 2) or (R,R)-TMCDA (3 and 4). In addition, complex 4 is a rare (R,R)-TMCDA adduct of sodium. In the solid state, complexes 5 and 6 exist as polymeric arrays of dimeric [{K∙chiral diamine}+{Mg(HMDS)3}−]2 subunits, with 5 adopting a two-dimensional net arrangement and 6 a linear arrangement. As such, complexes 5 and 6 appear to be the only structurally characterised complexes in which the chiral diamines (–)-sparteine (5) or (R,R)-TMCDA (6) have been incorporated within a polymeric framework. In addition, prior to this work, no (−)-sparteine or (R,R)-TMCDA adducts of potassium had been reported.
AB - Six alkali metal tris(HMDS) magnesiate complexes (HMDS, 1,1,1,3,3,3,-hexamethyldisilazide) containing chiral diamine ligands have been prepared and characterised in both the solid- and solution-state. Four of the complexes have a solvent-separated ion pair composition of the form [{M∙(chiral diamine)2}+{Mg(HMDS)3}−] [M = Li for 1 and 3, Na for 2 and 4; chiral diamine = (−)-sparteine for 1 and 2, (R,R)-TMCDA for 3 and 4, (where (R,R)-TMCDA is N,N,N′,N'-(1R,2R)-tetramethylcyclohexane-1,2-diamine)] and two have a contacted ion pair composition of the form [{K∙chiral diamine}+{Mg(HMDS)3}−]n [chiral diamine = (−)-sparteine for 5 and (R,R)-TMCDA for 6]. In the solid-state, complexes 1–4 are essentially isostructural, with the lithium or sodium cation sequestered by the respective chiral diamine and the previously reported anion consisting of three HMDS ligands coordinated to a magnesium centre. As such, complexes 1–4 are the first structurally characterised complexes in which the alkali metal is sequestered by two molecules of either of the chiral diamines (–)-sparteine (1 and 2) or (R,R)-TMCDA (3 and 4). In addition, complex 4 is a rare (R,R)-TMCDA adduct of sodium. In the solid state, complexes 5 and 6 exist as polymeric arrays of dimeric [{K∙chiral diamine}+{Mg(HMDS)3}−]2 subunits, with 5 adopting a two-dimensional net arrangement and 6 a linear arrangement. As such, complexes 5 and 6 appear to be the only structurally characterised complexes in which the chiral diamines (–)-sparteine (5) or (R,R)-TMCDA (6) have been incorporated within a polymeric framework. In addition, prior to this work, no (−)-sparteine or (R,R)-TMCDA adducts of potassium had been reported.
KW - sparteine-mediated deprotonation
KW - inverse crown-ether
KW - enantioselective lithiation-substitution
KW - carbon bond formations
KW - cation-pi interactions
KW - asymmetric-synthesis
KW - crystal-structures
KW - conjugate additions
KW - amide chemistry
KW - n-boc-pyrrolidine
U2 - 10.1039/c1dt10058k
DO - 10.1039/c1dt10058k
M3 - Article
VL - 40
SP - 5332
EP - 5341
JO - Dalton Transactions
JF - Dalton Transactions
SN - 1477-9226
IS - 19
ER -