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HERO ID
1070851
Reference Type
Journal Article
Title
Regio- and Stereoselectivity in the Reactions of Organometallic Reagents with an Electron-Deficient and an Electron-Rich Vinyloxirane: Applications for Sequential Bis-Allylic Substitution Reactions in the Generation of Vicinal Stereogenic Centers
Author(s)
Dieter, RK; Huang, Y; Guo, F
Year
2012
Is Peer Reviewed?
Yes
Journal
Journal of Organic Chemistry
ISSN:
0022-3263
EISSN:
1520-6904
Volume
77
Issue
11
Page Numbers
4949-4967
Language
English
PMID
22524502
DOI
10.1021/jo300304n
Abstract
Vinyloxiranes provide opportunities for bis-allylic substitution reactions and the generation of new vicinal stereogenic centers if regio- and stereocontrol can be achieved. Ethyl (E)-4,5-epoxy-2-hexenoate affords excellent S(N)2':S(N)2 regioselectivity and anti:syn product diastereoselectivity with dialkyzinc reagents in the presence of CuCN, and conversion of the resultant allylic alcohol to the acetate affords good syn:anti product diastereoselectivity in S(N)2'-selective allylic substitutions with alkylcyanocuprates in THF. (E)-1-(tert-Butyldimethylsilyloxy)-2,3-epoxy-4-hexenonate gives excellent S(N)2':S(N)2 regioselectivity and anti:syn product diastereoselectivity with dialkyzinc reagents in THF or DMF or Grignard reagents in Et(2)O/THF (10/1) in the presence of CuCN. Conversion of the product allylic alcohol into the allylic phosphate affords excellent S(N)2' regioselectivity and syn:anti product diastereoselectivity with lithium alkylcyanocuprates for primary and secondary alkyl transferable ligands, while S(N)2 regioselectivity is observed for the tert-butyl ligand. Reaction conditions have been developed for regio- and stereocontrolled bis-allylic substitution reactions on both electron-rich and electron-deficient alkenyloxiranes, providing a methodology for the generation of vicinal alkane stereogenic centers.
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IRIS
•
tert-Butanol
Considered Studies
Electronic Search
Excluded/ Not on Topic
Other Chemical/Non-tert-butanol
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