Complexation kinetics of dineopentylmagnesium with l-sparteine

Abstract

of the solvent, the residue was recrystallized from chloroformethanol, white needles, mp 239°(lit.27 239-240°), 92% after recrystallization. The uv absorption spectrum agreed with that published for DPP.9Techniques and apparatus used for voltammetry and coulometry have previously been described.11.28 TFA was reagent grade and used without further purification. Reagent grade dichloromethane was passed through a column of neutral aluminum immediately before use. Reagent grade TPE was recrystallized before use.

Highly Enantioselective Desymmetrization of Anhydrides by Carbon Nucleophiles: Reactions of Grignard Reagents in the Presence of (−)-Sparteine

“…The large majority of these investigations have focused on the use of (−)‐sparteine to achieve asymmetric reactions of organolithium reagents. The result described in Table 1, entry 5, represents a rare example in which (−)‐sparteine furnishes very good enantiocontrol for a reaction of a Grignard reagent 12, 13…”

Hydrolysis kinetics of (-)-sparteine-copper(II) halide

“…modes are expected for C2v complexes but frequently fewer are observed. 7 We find an X-insensitive band at approximately 240 cm"1 (Figure 1) which we have assigned to "co-(4-dmap) and two bands (Table IV) for the Cl and Br complexes which are assigned to vco-ci and vCo_Br. We have not resolved vCo-i or vco-NCSe absorptions from the low-frequency ligand bands (Figure 1).…”

“…M for the bromo complex and between 5.0 X 10~4 and 20 X KT4 M for the chloro complex. A best straight-line fit was obtained from the data (typically [5][6][7][8][9][10][11][12] readings per data point) by a least-squares computer fit.…”

Asymmetric Deprotonation with Alkyllithium–(−)‐Sparteine

“…Early investigations on organometallic (−)-sparteine complexes concern the nucleophilic addition of lithium 7 , magnesium 12 and zinc complexes 13,14 onto carbonyl compounds, utilization in polymerization 15,16 and also NMR spectroscopic investigations 17,18 .…”