Brønsted Acid Mediated Novel Rearrangements of Diarylvinylidenecyclopropanes and Mechanistic Investigations Based on DFT Calculations |
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Authors: | Wei Li Dr Min Shi Prof Dr Yuxue Li Dr |
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Institution: | State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032 (China), Fax: (+86)?21‐64166128 |
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Abstract: | Diarylvinylidenecyclopropanes undergo a novel rearrangement in the presence of the Brønsted acid Tf2NH (Tf: trifluoromethanesulfonyl) to give the corresponding naphthalene derivatives in good to high yields upon heating, whereas in the presence of the Brønsted acid toluene‐4‐sulfonic acid (p‐TSA), the corresponding triene derivatives are afforded in moderate to good yields under mild conditions. Corresponding mechanistic studies on the basis of density functional theory (DFT) with the Gaussian03 program by using the B3LYP method have revealed that the pKa value of the Brønsted acid, as well as the entropy and solvent effects, plays a significant role in this reaction; these factors can discriminate the differences in the reactivity and regioselectivity among the Brønsted acids used in this reaction. In the presence of Lewis acid Sn(OTf)2, a butatrienecyclopane can produce the corresponding ring‐opened products in moderate yields. |
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Keywords: | Brø nsted acids diarylvinylidenecyclopropanes Lewis acids naphthalenes reaction mechanisms regioselectivity trienes |
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