- Improved chiral olefin metathesis catalysts: Increasing the thermal and solution stability via modification of a C1-symmetrical N-heterocyclic carbene ligand
-
Four new ruthenium-based olefin metathesis catalysts that possess an N-heterocyclic carbene (NHC) ligand with benzyl (Bn) or or n-propyl (n-Pr) N-alkyl groups have been prepared. The synthetic routes developed for the synthesis of the required dihydroimid
- Savoie, Jolaine,Stenne, Brice,Collins, Shawn K.
-
supporting information; experimental part
p. 1826 - 1832
(2011/02/26)
-
- Titanium(IV)(salen) and yanadium(V)(salen) complexes derived from C 2- and C1-symmetric diamines for asymmetric cyanohydrin synthesis
-
Titanium and vanadium salen complexes have been prepared from C 2- and C1-symmetric acyclic diamines. All of the complexes catalysed the asymmetric addition of trimethylsilyl cyanide to benzaldehyde and the sense of asymmetric induction was determined by the nature of the substituents. The vanadium complex of a valine-derived diamine gave good results with a range of aromatic and aliphatic aldehydes. Georg Thieme Verlag Stuttgart.
- Belokon', Yuri N.,Hunt, Jamie,North, Michael
-
scheme or table
p. 2150 - 2154
(2009/05/07)
-
- Chiral bis(N-sulfonylamino)phosphine- and TADDOL-phosphite-oxazoline ligands: Synthesis and application in asymmetric catalysis
-
A series of N,P-ligands has been prepared, containing a chiral oxazoline ring and as a second chiral unit a bis(N-sulfonylamino)phosphine group embedded in a diazaphospholidine ring or a cyclic phosphite group derived from TADDOL. These modular ligands are readily synthesized from chiral amino alcohols and chiral 1,2-diamines or TADDOLs. Palladium and iridium complexes derived from these ligands were found to be efficient catalysts for enantioselective allylic alkylation and olefin hydrogenation, respectively.
- Hilgraf, Robert,Pfaltz, Andreas
-
-
- A new chiral masked form of glyoxal diimine
-
(3R,4R,5R,6R)-3,6-Diphenyl-N,N′-bis[(S)-1-phenylethyl]octa-1, 7-diene-4,5-diamine, by treatment with organolithium reagents RLi in controlled experimental conditions, underwent rearrangement and/or substitution of one or two branched allyl(s) by the R group(s). Hence, this diene behaves as a masked form of the chiral glyoxal diimine from that it is prepared, allowing the preparation of C1-symmetric 1,2-disubstituted 1,2-diamines, which are generally not available by the direct addition of organometallic reagents to the diimine, and C2-symmetric 1,2-diamines with good diastereoselectivities.
- Martelli, Gianluca,Savoia, Diego
-
p. 1531 - 1540
(2007/10/03)
-
- Synthesis of chiral C2-symmetric 1,2-diamines by the addition of organolithium reagents to N,N'-bis[(S)-1-phenylethyl]ethanediimine
-
The additions of alkyl-, phenyl- and vinyllithium reagents to N,N'-bis[(S)-1-phenylethyl]ethanediimine in THF at -78°C and in DME at -60°C gave high yields of 1,2-diamines with low stereocontrol. Care was taken to quench the reaction mixtures with de-aera
- Martelli, Gianluca,Morri, Stefano,Savoia, Diego
-
p. 8367 - 8374
(2007/10/03)
-
- A practical and efficient synthesis of enantiomerically pure di-tert- butylethanediamine
-
A diastereoselective synthesis of 1,2-diamino-1,2-di-tert-butylethane has been developed by addition of tert-butyl magnesium chloride to a chiral bis-imine derived from glyoxal and (S)-methylbenzylamine. Addition of the bis-imine to the Grignard reagent i
- Roland, Sylvain,Mangeney, Pierre,Alexakis, Alex
-
p. 228 - 230
(2007/10/03)
-