Indole-3-carboxaldehyde, conversion

Indole, 1-methyl-, 40, 68 Indole-3-acetic acid, 44, 64 Indoleacetonitrile, 44, 65 Indole-3-carbonitrile, 43, 58 Indole-3-carboxaldehyde, conversion to indole-3-carbonitrile, 43, 58 Indole-2-carboxylic acid, ethyl ESTER, 43, 40... 

Decarbonylation decarboxylation. At 110-170° this complex in catalytic amounts effects decarbonylation of simple aldehydes in quantitative yield.- Decarbonylation of typical indole-2-carboxaldehydes with in j/ M-generated catalyst proceeds in 82-95% yield. In fact, decarboxylation of some indole-2-carboxylic acids can be effected in higher overall yield by conversion to the aldehyde (LiAlH4 MnO,) followed by decarbonylation than by copp)er-catalyzed decarboxylation. ... 

Interestingly, when the same indole-3-carboxaldehyde derivative 65 is subjected to Diels-Alder reactions with Danishefsky s diene (52), either under thermal or hyperbaric activation, it is the aldehyde and not the indole carbon-carbon double bond that serves as the dienophilic component (Scheme 19) [34]. The hetero-Diels-Alder reaction with the carboxaldehyde proceeded at quantitative conversion (82% yield) under thermal conditions (12 equiv Danishefsky s diene, 170°C, 24 h) and provided the cycloadduct 69 in quantitative yield under hyperbaric conditions (12 equiv Danishefsky s diene, 45°C, 96 h, 12 kbar). 

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