Improved Methodology for the Preparation of Chiral Amines

Appendix
Experimental Section
General Remarks
NMR spectra were recorded on a JEOL ECX 400 spectrometer, operating at 400 MHz ( 1 H)
and 100 MHz ( 13 C) respectively. Chemical shifts (δ) were reported in parts per million (ppm)
downfield from TMS (= 0) or relative to CHCl 3 (7.26 ppm) or D 2 O (4.79 ppm) for 1 H NMR.
For 13 C NMR, chemical shifts were reported in the scale relative to CHCl 3 (77.0 ppm) or D 2 O
(CH 3 OH internal reference, δ= 49.5 ppm) as an internal reference. Multiplicities are
abbreviated as: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br, broad. The
coupling constants are expressed in Hz. FTIR spectra were obtained on Nicolet Avatar 370
spectrometer. Mass spectra were recorded on a Finnigan MAT 95 (EI) with an ionization
potential of 70 eV. Elemental analyses were performed by an external vendor in Lindlar,
Germany on an Elementar Vario EL III instrument. For amine products 2, reaction progress
and diastereomeric excess measurements were obtained using a Shimadzu GC-2010
instrument with a Rtx-5 amine column (Restec, 30 m x 0.25 mm); T inj = 300 °C and T det =
300 °C, and carrier gas He @ 24 psi were always constant. Program A: 50 °C (1 min), then
14 °C/min to 280 °C (hold 2 min); Program B: 50 °C (1 min), then 14 °C/min to 130 °C (hold
9 min), then 20 °C/min to 280 °C (hold 2 min); Program C: 50 °C (1 min); then 14 °C/min to
280 °C (hold 1 min); Program D: 50 °C (1 min); then 14 °C/min to 280 °C (hold 5 min). For
hydrogenolyzed product primary amine 4d the enantiomeric excess of the trifluoroacetamide
derivative was determined by gas chromatography using a Shimadzu GC-2010 instrument on
a Chiraldex B-DP column (Astec, 30 m x 0.25mm); T inj = 200 °C, T det = 200 °C, and carrier
gas He @ 24 psi were constant. Program E: 130 °C (20 min), then 20 °C/min to 180 °C (hold
10 min), split ratio 60:1. Column chromatography was performed using silica gel 60 (0.040-
0.063 mm). Thin-layer chromatography (TLC) was performed using precoated plates of silica
gel 60 F 254 and visualized under ultraviolet irradiation (254 nm).
All reactions were performed under an inert atmosphere (nitrogen). All reagents were
obtained from Sigma-Aldrich (except cyclohexyl methyl ketone, obtained from ABCR
GmbH &Co) and used without further purification. Before using the commercially purchased
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