Enantioselective Synthesis with Lithium/(−)‐Sparteine Carbanion Pairs

Abstract

[(q5-C,H,)Re(NO)(PPh3)]+ and analogons unsaturated chiral complexes (see element symbols along the fingertips) can form two diastereomeric adducts with prochiral alkenes, aldehydes, and ketones. The ratio of these diastereomers is a measure of the chiral recognition, symbolized by the hands, of the reaction partners. The rhenium complex mentioned is depicted above the hands (Re: light gray, P: yellow, N: light blue, 0: dark blue, Ph, Cp: dark gray). The selectivity of alkene complexation can be analyzed (and predicted) by considering the sizes of the substituents a 4 on the alkene and correlating them with the steric conditions in the chiral complexes, which can be represented with three-dimensional bar graphs.

(−)-Sparteinium tetrachloridozincate monohydrate

“…The ligand esp is sparteine, also known as lupinidine, an alkaloid having four chiral centres and two protonable N sites. For the structure reported here, (-)-sparteine was used, which has the RSSS configuration (Hoppe & Hense, 1997). The same arrangement of ions and lattice water in the crystal is observed with Zn II and Cu II .…”

Investigation of bispidines as the stoichiometric ligand in the two-ligand catalytic asymmetric deprotonation of N-boc pyrrolidine

“…1,2 In this context, (-)-sparteine is the most widelyinvestigated diamine 3 following the pioneering work by Hoppe 4 and Beak. 5 Indeed, reagents comprising organolithium reagents (e.g.…”

Enantioselective Addition of Grignard Reagents to Aldehydes

“…The use of chiral aminoalcohol to lead asymmetrically nucleophilic additions of organometallics to carbonyl compounds is a field of great potentiality in synthesis [1]. It is based on the coordination of amines and ethers to organolithium and Grignard reagents; the efficiency of the asymmetric induction depends, among other factors, on the characteristics of the metal [2], its aggregation state [3] and on the chiral ligand structure [4].…”