Preparation of Alkyl-Substituted Indoles in the Benzene Portion. Part 11. Total Synthesis of (6R,8S)-Herbindole A, (6R,8S)-Herbindole B, (6R,8S)-Herbindole C, (6R,8S)-cis-Trikentrin A, (6R,8S)-cis-Trikentrin B, (6R,8R)-trans-Trikentrin B, and (6R,8R)-iso-trans-Trikentrin B. Determination of the Absolute Structures of Natural Herbindoles and Trikentrins.