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Bew, Sean P. 
ORCID: https://orcid.org/0000-0002-9087-9463, Davies, Stephen G. and Fukuzawa, Shin‐Ichi
(2000)
Kinetic resolution of alpha-acetoxy carboxylic acids with homochiral SuperQuats.
Chirality, 12 (5-6).
pp. 483-487.
ISSN 0899-0042
Abstract
Preliminary investigations focused on the kinetic resolution of (+)-alpha-acetoxy mandelic carboxylic acid chloride with isopropyl SuperQuat and isopropyl Evans' homochiral auxiliaries. The addition of 2 equiv. of the acid chloride to the lithium salts of the auxiliaries (SuperQuat and Evans') at -100 degrees C in the THF afforded the corresponding N-acyl auxiliaries in high chemical yields (95% and 89%) and d.e.'s of 66% and 40%, respectively. Using the same mandelic acid chloride but incorporating SuperQuat aux iliaries derived from (S)-phenylglycine and (S)-phenylalanine yielded the corresponding N-acyl SuperQuats in 86% and 90% and d.e.'s of 66% and 30%, respectively. Substituting the phenyl group within the cr-acetoxy mandelic acid chloride for a n-butyl, tert-butyl and cyclohexyl group changed the d.e. significantly when kinetically resolved with isopropyl SuperQuat. The yields were all similar, i.e., similar to 90% but the d.e.'s varied considerably, with values of 20%, 50%, and 82%, respectively. Attempted kinetic resolution of alpha-methoxy-phenylacetyl chloride using the lithium salt of isopropyl SuperQuat revealed a diasteroselectivity of 45%, significantly lower than that obtained with the corresponding alpha-acetoxy carboxylic acid chlorides. (C) 2000 Wiley-Liss, Inc.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Chemistry (former - to 2024) |
| UEA Research Groups: | Faculty of Science > Research Groups > Synthetic Chemistry (former - to 2017) Faculty of Science > Research Groups > Chemistry of Materials and Catalysis |
| Depositing User: | Rachel Smith |
| Date Deposited: | 20 Apr 2011 09:04 |
| Last Modified: | 24 Sep 2024 10:26 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/29667 |
| DOI: | 10.1002/(SICI)1520-636X(2000)12:5/6<483::AID-CHIR33>3.0.CO;2-D |
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