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Experimental and theoretical investigations into the unusual regioselectivity of 4,5-, 5,6-, and 6,7-indole aryne cycloadditions.

ABSTRACT: The 6,7-indolyne shows remarkable regioselectivity in its cycloaddition with 2-substituted furans. Electron-donating groups give predominantly the more sterically crowded product, while electron-withdrawing groups display the opposite regioselectivity. By contrast, 4,5- and 5,6-indolynes show no regioselectivity. Optimized electronic structure calculations using the M06-2X density functional and 6-311+G(2df,p) basis set revealed that the 6,7-indolynes are highly polar structures and that their cycloadditions have substantial electrophilic substitution character that leads to the observed preference for contrasteric products.

SUBMITTER: Garr AN

PROVIDER: S-EPMC4175992 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature

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Experimental and theoretical investigations into the unusual regioselectivity of 4,5-, 5,6-, and 6,7-indole aryne cycloadditions.

Garr Ashley N AN Luo Diheng D Brown Neil N Cramer Christopher J CJ Buszek Keith R KR VanderVelde David D

Organic letters 20100101 1

The 6,7-indolyne shows remarkable regioselectivity in its cycloaddition with 2-substituted furans. Electron-donating groups give predominantly the more sterically crowded product, while electron-withdrawing groups display the opposite regioselectivity. By contrast, 4,5- and 5,6-indolynes show no regioselectivity. Optimized electronic structure calculations using the M06-2X density functional and 6-311+G(2df,p) basis set revealed that the 6,7-indolynes are highly polar structures and that their c ...[more]

PMID: 19961152

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