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Supplementary Information for:
Highly stereoselective construction of the C2 stereocentre of α-‐tocopherol (vitamin E) by asymmetric addition of Grignard reagents to ketones
Bartosz Bieszczad and Declan G. Gilheany*
Centre for Synthesis and Chemical Biology, School of Chemistry
University College Dublin,
Belfield, Dublin 4, Ireland
Email: [email protected]
Contents:
1. General experimental..............................................................................................................2
2. NMR spectra of products and intermediates..........................................................................2
3. Chromatograms of 1-‐(2,5-‐dimethoxy-‐3,4,6-‐trimethylphenyl)-‐3,7,11,15-‐tetramethylhexadecan-‐3-‐ol (1)..............................................................................................12
Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry.This journal is © The Royal Society of Chemistry 2017
2
1. General Experimental
All chemicals were supplied by Aldrich apart from natural phytol, which was supplied by Wuhan ChemFaces
Biochemical Co. Microwave assisted reactions were performed using CEM Discover microwave instrument (S-‐
series). Supercritical Fluid Chromatography (SFC) analysis was made using ACQUITY UPC2 system with auto-‐
sampler, combined with PDA Detector Type UPLC eLambda 800 nm. Chiral column Chiralpak® IA-‐3 of internal
diameter of 4.6 mm, 100 mm with particles size of 3 µm was used to separate diastereoisomers in a single case
with methanol as a co-‐solvent. Samples were prepared in heptanes in approximately 1 mg/mL. All NMR analysis
was performed using 300, 400 or 500 MHz Varian spectrometers. NMR samples were made in CDCl3. 1H and 13C
NMR chemical shifts are given relative to tetramethylsilane.
2. NMR spectra of products and intermediates
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11
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3. Chromatograms of 1-‐(2,5-‐dimethoxy-‐3,4,6-‐trimethylphenyl)-‐3,7,11,15-‐tetramethylhexadecan-‐3-‐ol (1)
(i) SCF Chromatograms of high dr materials from Route 3
a) (R,R,R) and (S,R,R) – (50 : 50 dr)
b) (S,R,R) – diastereoisomer – 95 : 5 dr
c) (R,R,R) – diastereoisomer – 96 : 4 dr
(ii) Best HPLC Chromatograms (OJH column, resolution = 0.4)
a) (R,R,R) and (S,R,R) – (50 : 50 dr) :
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b) (R,R,R) – diastereoisomer of high dr from Route 3
c) (R,R,R) – diastereoisomer of moderate dr from Route 2
(iii) SCF Chromatogram: (S,R,R) – diastereoisomer of moderate dr from Route 1