Tetrahydrobenzo / carbazoles

DFT calculations on the intramolecular Diels-Alder reaction of penta-l,3-dienyl acrylates predict stereoselectivities that are in good agreement with the experimen- (g) tal results.85 Another DFT study at the B3LYP/6-31G(d) level of the intramolecular Diels-Alder cycloaddition of 5-vinylcyclohexa-1,3-dienes has been reported. Reaction rates are influenced by dienophile twisting and substituent effects.86 The intramolecular dehydro-Diels-Alder reactions of ynamides (79) provides a new synthesis of benzo[fc]-, tetrahydrobenzo[fc]-, naphtho[l,2-/j -, and dibenzo[a,c]carbazoles... 

The reactions of 2-bromonaphthoquinone (221, R = H) and 3-bromo-juglone (221, R = OH) with enaminones 222 gave regioselectively benzo-[/ Jindoles or tetrahydrobenzo[/i]carbazoles 223, Scheme 59. This modification of the Nenitzescu reaction opened up new entries to the Kinamycin alkaloid framework (92TL535). 

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