Synthesis and Characterization of Norbornanediol Isomers and Their Fluorinated Analogues

Abstract

[reaction: see text] Fluorinated norbornene monomers exhibit the requisite properties for inclusion in 157 nm photoresists, but traditional addition and radical polymerizations with these monomers have failed. Norbornanediols provide an alternate route to these materials via condensation polymerization, and methods have been developed for the efficient synthesis of the exo-2-syn-7- and endo-2-exo-3-dihydroxynorbornanes. Synthesis of the fluorinated analogues is complicated by steric and electronic effects; however, a high-yielding synthesis of endo-2-exo-3-dihydroxynorbornane bearing a 5-endo-[2,2-bis(trifluoromethyl)hydroxyethyl] substituent is reported.

A Thermally Stable SO2-Releasing Mechanophore: Facile Activation, Single-Event Spectroscopy, and Molecular Dynamic Simulations

“…Next, an osmium-catalyzed dihydroxylation reaction using citric acid as an additive provided 2 in 62% yield . The exo product was observed as the only diastereomer, consistent with the general diastereoselectivity observed in the dihydroxylation of norbornene-like structures . A subsequent two-step sequence of acylation and ring-closing metathesis afforded macrocycle 4 as an E / Z mixture in 81% yield.…”

“…52 The exo product was observed as the only diastereomer, consistent with the general diastereoselectivity observed in the dihydroxylation of norbornene-like structures. 53 A subsequent two-step sequence of acylation and ring-closing metathesis afforded macrocycle 4 as an E/Z mixture in 81% yield. The stereochemistry of 4 was confirmed to be the exo product by X-ray crystallography (Scheme 2).…”

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

“…Unfortunately, hydride reduction of cyclic anhydrides is reported to produce lactones [23]; hence, we first saponified 7-ketonadic anhydride 1 to the corresponding diacid in situ. Subsequent NaBH 4 reduction provides an 80% yield of the 7-hydroxynadic diacid (2) in an anti to syn ratio (with respect to the olefin linkage) of 93:7. These isomers were identified and fully Fluorinated norbornenes are very desirable monomers in the semiconductor and high-temperature polyimide industries.…”

“…Fluorinated norbornenes are very desirable monomers in the semiconductor industry -for the production of optical lithography polymers [2][3][4], and in the preparation of fluorinated end-caps for use in high temperature polyimide polymers [5].…”