752232-62-5Relevant articles and documents
Metal complexes of chiral NHCs containing a fused six- and seven-membered central ring
Newman, Paul D.,Cavell, Kingsley J.,Kariuki, Benson M.
, p. 2724 - 2734 (2010)
Azolium precursors to expanded-ring NHCs incorporating a chiral bicyclic skeleton derived from (1R)-camphor with N,N′-dibenzyl or N,N′-dipyridyl substituents have been prepared and used for the synthesis of a number of metal complexes of the resultant NHCs. The bicyclic framework contains two fused rings, one of which is seven-membered while the other is six-membered. Deprotonation of (1R,5S)-2,4-dibenzyl-1,8,8-trimethyl-4-aza-2- azoniabicyclo[3.2.1]oct-2-ene hexafluorophosphate, 1a· HPF6, produces a solution of free carbene , 1a, that can be used for the preparation of [Ag(1a)2]OTf (2a), [Rh(1,5-COD)(1a)Cl] (3a), [Rh(CO)2(1a)Cl] (4a), and [Ir(1,5-COD)(1a)Cl] (5a) complexes. The fused expanded ring NHC ligands display properties and reactivity patterns more akin to those of five-membered NHCs rather than monocyclic six- or seven-membered NHCs. Consistent with this premise, the red Ni(II) pincer complex [Ni(η3-C8H13)(1b)]PF6, 6b, was obtained via oxidative addition of the azolium salt 1b·HPF6 to Ni(1,5-COD)2 in THF. This is the first unambiguous example of a saturated and/or expanded ring NHC oxidatively adding to a low-valent metal center. A single-crystal X-ray structure determination of 6b showed the NHC to be coordinated in a pincer fashion through the carbene and two pyridine nitrogens at a square-pyramidal nickel(II) center. One of the original 1,5-COD ligands has undergone a 1,5 to 1,3 isomerization before migratory insertion of one of the alkene groups into the Ni-H function, generated on oxidative addition of the azolium salt, to give the allylic η3-C8H 13 ligand. When 6b was dissolved in CHCl3 or CH 2Cl2 in air, the allyl ligand was lost and a chloride was abstracted from the solvent to give yellow square-planar [Ni(1b)Cl]PF 6, 7b, the structure of which was confirmed by single-crystal X-ray techniques.
Enantioselective alkylation of aromatic aldehydes with (+)-camphoric acid derived chiral 1,3-diamine ligands
Serra, M. Elisa Silva,Murtinho, Dina,Paz, Victória
, p. 381 - 386 (2017/02/18)
A series of chiral 1,3-diamine ligands derived from (+)-camphoric acid were prepared from the reaction of 1,3-diamino-1,2,2-trimethylcyclopentane with aromatic aldehydes, followed by reduction of the corresponding diimines. These newly synthesized ligands
Straightforward Diastereoselective Synthesis of P-Chirogenic (1R)-1,8,8-Trimethyl-2,4-diaza-3-phosphabicyclo[3.2.1]octane 3-Oxides: Application as Chiral NMR Solvating Agents
Uzarewicz-Baig, Magdalena,Wilhelm, René
, p. 121 - 134 (2016/04/01)
A direct route to enantio- and diastereopure nitrogen-substituted phosphine oxides has been developed. The desired P-stereogenic compounds were obtained in good yields and high purity. The starting point of the synthesis was (+)-camphor, which is a readil
New enantiopure NHCs derived from camphor
Reddy, Peddiahgari Vasu Govardhana,Tabassum, Sobia,Blanrue, Amelie,Wilhelm, Rene
supporting information; experimental part, p. 5910 - 5912 (2010/01/31)
A new class of enantiopure carbene precursors based on cheap camphor has been developed, and a restricted rotation of one N-substituent due to the C-10 methyl group of the camphor skeleton has been found; in situ prepared corresponding carbenes revealed t
Synthesis of a new chiral cyclic o-hydroxynaphthylphosphonodiamide and its application as ligand catalyst in asymmetric silylcyanation of aromatic aldehydes
He, Ke,Zhou, Zhenghong,Wang, Lixin,Li, Kangying,Zhao, Guofeng,Zhou, Qilin,Tang, Chuchi
, p. 1521 - 1524 (2007/10/03)
A new chiral cyclic o-hydroxynaphthylphosphonodiamide (+)-2 was synthesized starting from (+)-cis-1,2,2-trimethylcyclopentane-1,3-diamine. The absolute configuration of phosphorus atom was determined as S by X-ray diffraction analysis. Excellent enantiose
Synthesis of some new chiral bifunctional o-hydroxyarylphosphonodiamides and their application as ligands in Ti(IV) complex catalyzed asymmetric silylcyanation of aromatic aldehydes
He, Ke,Zhou, Zhenghong,Wang, Lixin,Li, Kangying,Zhao, Guofeng,Zhou, Qilin,Tang, Chuchi
, p. 10505 - 10513 (2007/10/03)
Some new chiral bifunctional o-hydroxyarylphosphonodiamides were synthesized starting from (+)-cis-1,2,2-trimethylcyclopentane-1,3-diamine and the absolute configuration of the phosphorus atom was determined by X-ray diffraction analysis. Excellent enantioselectivity (up to 98% ee) was achieved in asymmetric silylcyanation of aromatic aldehydes using a chiral titanium complex formed in situ from Ti(OiPr)4 and o-hydroxyarylphosphonodiamide as the catalyst. Graphical Abstract.
