Chiral Tertiary Diamines in Asymmetric Synthesis

Bidirectional Metalation of Hydrobenzoin: Direct Access to New Chiral Ligands and Auxiliaries

“…In a catalytic process, a ligand that is present in sub-stoichiometric quantities, coordinates to the prochiral material in a non-covalent manner prior to the stereoselective reaction and thus precludes both the appendage and removal steps required with chiral auxiliaries. The transfer of asymmetry in these reactions is often fine-tuned by the choice of metal and/or chiral ligand; widely used chiral ligands include various diols, 7 as well as diamines, 8 and diphosphines (Figure 1). 9 …”

Synthesis of chiral 1-(2-aminoalkyl)aziridines via the self-opening reaction of aziridine

“…Moreover, such compounds play a special role in asymmetric synthesis, including both transition-metalcatalyzed and organocatalytic transformations. [3][4][5] Consequently, numerous strategies have been developed for the synthesis of 1,2-diamines, including diastereo-and enantioselective examples, with continued efforts to improve their efficiency and selectivity. One of the methods providing 1,2-diamines is the reaction of a nitrogen-nucleophile opening an aziridine ring.…”

Reactions of (−)-sparteine with alkali metal HMDS complexes: conventional meets the unconventional

“…To complete the structure of the cation, a HMDS anion bridges between the two metal centres, resulting in a distorted trigonal planar arrangement around Na1 (sum of angles, 354.11). The only previously reported complex which incorporates both sodium and (À)-sparteine is [(À)-sparteineÁNaMg(TMP) 2 n Bu]. 15 The Na centre adopts a distorted tetrahedral geometry in this complex, as a consequence its mean Na-N (À)…”

“…When (À)-sparteine w a ss u b j e c t e dt oav a c u u mf o rt w oh o u r sp r i o rt ou s e -i na n attempt to remove volatiles such as entrained H 2 O-crystals of 3 were not forthcoming. Instead a microcrystalline material (2) precipitated from solution at À28 1C. Unfortunately, this material was not suitable for X-ray crystallographic analysis.…”