Stereospecific mono- and difluorination of the C7-bridge of norbornenes

David E. Rajsfus; Sari Alter-Zilberfarb; Pessia Sharon; Mary Ann B. Meador; Aryeh A. Frimer

doi:10.1016/j.jfluchem.2011.03.009

Stereospecific mono- and difluorination of the C₇-bridge of norbornenes

David E. Rajsfus
, Sari Alter-Zilberfarb
, Pessia Sharon
, Mary Ann B. Meador
, Aryeh A. Frimer

Department of Chemistry

Bar-Ilan University
NASA Glenn Research Center

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

Fluorinated norbornenes are very desirable monomers in the semiconductor and high-temperature polyimide industries. We describe herein a synthetic strategy for the stereospecific mono- or difluorination of the C ₇-carbon in norbornene systems beginning with 7-ketonadic anhydride 1. In particular, anti-7-fluoro methyl diester 4 and its 7,7-difluoronadic analog 7 can be prepared from 1 in 3 or 4 steps: saponification, reduction (for 4), esterification, fluorination with DAST. In addition, anti-7-fluoro-syn-7- fluoromethylnadic diester 16 is obtained from epoxide 14, and dimethyl 7,7-difluorobicyclo[2.2.2]oct-5-ene-2,3-dicarboxylate (17) from ketone 15. Anchimeric assistance of the norbornene double bond guides the introduction of attacking fluoride anions stereospecifically anti to the olefinic linkage.

Original language	English
Pages (from-to)	339-347
Number of pages	9
Journal	Journal of Fluorine Chemistry
Volume	132
Issue number	5
DOIs	https://doi.org/10.1016/j.jfluchem.2011.03.009
State	Published - May 2011

Keywords

7,7-Difluoronadic
7-Fluoronadic
Anchimeric assistance
Diethylaminosulfur trifluoride
Stereospecific fluorination

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10.1016/j.jfluchem.2011.03.009

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title = "Stereospecific mono- and difluorination of the C7-bridge of norbornenes",

abstract = "Fluorinated norbornenes are very desirable monomers in the semiconductor and high-temperature polyimide industries. We describe herein a synthetic strategy for the stereospecific mono- or difluorination of the C 7-carbon in norbornene systems beginning with 7-ketonadic anhydride 1. In particular, anti-7-fluoro methyl diester 4 and its 7,7-difluoronadic analog 7 can be prepared from 1 in 3 or 4 steps: saponification, reduction (for 4), esterification, fluorination with DAST. In addition, anti-7-fluoro-syn-7- fluoromethylnadic diester 16 is obtained from epoxide 14, and dimethyl 7,7-difluorobicyclo[2.2.2]oct-5-ene-2,3-dicarboxylate (17) from ketone 15. Anchimeric assistance of the norbornene double bond guides the introduction of attacking fluoride anions stereospecifically anti to the olefinic linkage.",

keywords = "7,7-Difluoronadic, 7-Fluoronadic, Anchimeric assistance, Diethylaminosulfur trifluoride, Stereospecific fluorination",

author = "Rajsfus, \{David E.\} and Sari Alter-Zilberfarb and Pessia Sharon and Meador, \{Mary Ann B.\} and Frimer, \{Aryeh A.\}",

year = "2011",

month = may,

doi = "10.1016/j.jfluchem.2011.03.009",

language = "אנגלית",

volume = "132",

pages = "339--347",

journal = "Journal of Fluorine Chemistry",

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T1 - Stereospecific mono- and difluorination of the C7-bridge of norbornenes

AU - Rajsfus, David E.

AU - Alter-Zilberfarb, Sari

AU - Sharon, Pessia

AU - Meador, Mary Ann B.

AU - Frimer, Aryeh A.

PY - 2011/5

Y1 - 2011/5

N2 - Fluorinated norbornenes are very desirable monomers in the semiconductor and high-temperature polyimide industries. We describe herein a synthetic strategy for the stereospecific mono- or difluorination of the C 7-carbon in norbornene systems beginning with 7-ketonadic anhydride 1. In particular, anti-7-fluoro methyl diester 4 and its 7,7-difluoronadic analog 7 can be prepared from 1 in 3 or 4 steps: saponification, reduction (for 4), esterification, fluorination with DAST. In addition, anti-7-fluoro-syn-7- fluoromethylnadic diester 16 is obtained from epoxide 14, and dimethyl 7,7-difluorobicyclo[2.2.2]oct-5-ene-2,3-dicarboxylate (17) from ketone 15. Anchimeric assistance of the norbornene double bond guides the introduction of attacking fluoride anions stereospecifically anti to the olefinic linkage.

AB - Fluorinated norbornenes are very desirable monomers in the semiconductor and high-temperature polyimide industries. We describe herein a synthetic strategy for the stereospecific mono- or difluorination of the C 7-carbon in norbornene systems beginning with 7-ketonadic anhydride 1. In particular, anti-7-fluoro methyl diester 4 and its 7,7-difluoronadic analog 7 can be prepared from 1 in 3 or 4 steps: saponification, reduction (for 4), esterification, fluorination with DAST. In addition, anti-7-fluoro-syn-7- fluoromethylnadic diester 16 is obtained from epoxide 14, and dimethyl 7,7-difluorobicyclo[2.2.2]oct-5-ene-2,3-dicarboxylate (17) from ketone 15. Anchimeric assistance of the norbornene double bond guides the introduction of attacking fluoride anions stereospecifically anti to the olefinic linkage.

KW - 7,7-Difluoronadic

KW - 7-Fluoronadic

KW - Anchimeric assistance

KW - Diethylaminosulfur trifluoride

KW - Stereospecific fluorination

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AN - SCOPUS:79955596906

SN - 0022-1139

VL - 132

SP - 339

EP - 347

JO - Journal of Fluorine Chemistry

JF - Journal of Fluorine Chemistry

IS - 5

ER -

Stereospecific mono- and difluorination of the C₇-bridge of norbornenes

Abstract

Keywords

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