Nucleophilic Addition to C, C‐Double Bonds. IV. Ether formation by intramolecular addition to unsymmetrically alkyl‐substituted C, C‐double bonds

Abstract

Tricyclic olefinic alcohols containing an unsymmetrically alkyl‐substituted C, C‐double bond were cyclized intramolecularly to their corresponding ethers under basic conditions: 9 → 12, 10 → 17 + 18, and 11 → 12 (Scheme 3, Table 1). The reactivity is mainly due to relieve of ground state strain. Alcohol 9 (endocyclic double bond) isomerized under intramolecular assistance by the hydroxyl group to 11 (exocyclic double bond) before cyclization to 12 occurred (Scheme 5). The latter step being the faster one, no isomerization 11 → 9 was observed.

ChemInform Abstract: Conformational Analysis of Bicyclo(3.3.1)nonane‐exo‐2,exo‐4‐dicarboxylic Acid Derivatives and Related Compounds.

“…Ketone 4 could not be reduced under these conditions due to its thermal instability3". It is known that LiAlH4 reduction of some of these ketones (1 29), 13", 431)) leads stereoselectively, as expected, to the corresponding syn-alcohols, while Na/2propanol reduction of ketone 2") gives a mixture of alcohol 10 (43% yield) and its C-9 epimer (6% yield) among other reduction products. Acetylation of these alcohols with acetic anhydride gave the corresponding acetates 9a, 10a33), and 11 a, respectively.…”

Conformational analysis of bicyclo[3.3.1]nonane‐exo‐2,exo‐4‐dicarboxylic acid derivatives and related compounds

“…Ketone 4 could not be reduced under these conditions due to its thermal instability3". It is known that LiAlH4 reduction of some of these ketones (1 29), 13", 431)) leads stereoselectively, as expected, to the corresponding syn-alcohols, while Na/2-propanol reduction of ketone 2") gives a mixture of alcohol 10 (43% yield) and its C-9 epimer (6% yield) among other reduction products. Acetylation of these alcohols with acetic anhydride gave the corresponding acetates 9a, 10a33), and 11 a, respectively.…”

An investigation into the formation of benzo- and naphtho-pyrans by cyclisation of ortho-alkenyl(hydroxyalkyl)benzenes using either cerium(IV) ammonium nitrate or potassium t-butoxide in dimethylformamide

“…We have also shown that the naphthalenes (1) and (2) cyclise rapidly and in high yield to give the naphthopyrans (9) and (1 1) respectively using potassium t-butoxide in dimethylformamide under anaerobic conditions. In the first case, compound (9) was shown to be the initial product, since longer treatment under the same conditions caused epimerisation to the cis-isomer (10).…”