Synthesis, modification, and characterization of a family of homologues of exo-calix

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Authors
Burns, Dennis H.
Chan, Ho-Kit
Miller, Jeffrey D.
Jayne, Charles L.
Eichhorn, David M.
Advisors
Issue Date
2000-08-25
Type
Article
Keywords
Research Projects
Organizational Units
Journal Issue
Citation
The Journal of organic chemistry. 2000 Aug 25; 65(17): 5185-96.
Abstract

A general strategy for the preparation of the family of exo-[n.m.n.m]metacyclophanes (n,m > or = 3) in 6-steps (starting from 2-bromoanisole) that utilizes a [2 + 2] approach to furnish the exo-metacyclophane ring in good to moderate yield is described. The soluble copper catalyst [CuBr-LiSPh-LiBr-THF] is used to efficiently couple Grignard and alkyl or ether tosylate reagents in several of the synthetic steps, including the ring construction in the final step. The exo-[n.m.n.m]metacyclophane ring is conformationally mobile on the NMR time scale, and X-ray crystallography reveals that exo-[3.3.3.3]metacyclophane 2a assumes a cone conformation, and that exo-[6.6.6.6]metacyclophane 6a assumes a chair conformation. Molecular mechanics calculations show that both conformations for each exo-metacyclophane are very similar in energy. Regiocontrol over the alkylation and acylation of the phenolic oxygens of 2b is problematic, although the preparation of the tetraacetylated 18 and alkylation of 2b with CH2BrCl to furnish the methylene-linked mono- and bis-adducts 19 and 20 are straightforward.

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Full text of this article is not available in SOAR.
Publisher
American Chemical Society
Journal
Book Title
Series
The Journal of organic chemistry
J. Org. Chem.
PubMed ID
DOI
ISSN
1520-6904
0022-3263
EISSN