Journal article
Stereocontrol in hydride addition to ketone-derived chiral N-acylhydrazones
Tetrahedron, Vol.59(34), pp.6393-6402
2003
DOI: 10.1016/S0040-4020(03)01091-3
Abstract
Chiral N-acylhydrazones derived from various aldehydes and N-amino-4-benzyl-2-oxazolidinone have previously been shown to be effective for acyclic stereocontrol of intermolecular radical and allylsilane additions. Treatment of the propionaldehyde hydrazone with tributyltin hydride in the presence of boron trifluoride etherate led to rapid chemoselective reduction of the imine bond in high yield. Preparation of similar hydrazones from ketones led to E/ Z isomer mixtures, usually in ratios of 4:1 or greater. Geometry of the CN bond was assigned by steric compression shifts in 13C NMR spectra. Reduction with tributyltin hydride and boron trifluoride etherate afforded diastereomer mixtures in ratios very similar to the original E/ Z isomer ratios. The chiral auxiliary blocked the opposite face of the CN bond relative to a related process using a chelated Lewis acid. A stereocontrol model involving monodentate interaction of the N-acylhydrazone and boron trifluoride is consistent with the observed stereochemical outcome. Graphic
Details
- Title: Subtitle
- Stereocontrol in hydride addition to ketone-derived chiral N-acylhydrazones
- Creators
- Jun QinGregory K Friestad
- Resource Type
- Journal article
- Publication Details
- Tetrahedron, Vol.59(34), pp.6393-6402
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/S0040-4020(03)01091-3
- ISSN
- 0040-4020
- eISSN
- 1464-5416
- Language
- English
- Date published
- 2003
- Academic Unit
- Chemistry
- Record Identifier
- 9983985712302771
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