Studies On The Total Synthesis Of Several Terpenoid Natural Products

This thesis main focused on the total syntheses of three terpenoid natural products. A novel approach for synthesis of aromatic tricyclic diterpenoid comounds, in which intramolecular cyclization and Friedel-Crafts alkylation took place simultaneously. By using linchpin-coupling protocol construct the five membered ring as key step, (S)-(-)-4-tert-Butyldimethysiloxy- 2-cyclopenten-l-one was synthesized. Include the following four parts:Chapter 1. The progress on the study of the Brook rearrangement in tandem bond formation stragegies (review)Some general example of Brook rearrangement in tandem bond formation stragegies and application in syntheses were reviewed, meanwhile, its mechanism, reaction condition and new reagents also were discussed.Chapter 2. The first total synthesis of Salvirecognine and related approach studiesThe definition, classification of aromatic tricyclic diterpenoid comounds, and previous synthetic reports of them were introduced briefly. A novel approach has been found and the first total synthesis of (±)-Salvirecognine was accomplished. In which intramolecular cyclization and Friedel-Crafts alkylation took place simultaneously to afford key intermediates for synthesis of aromatic tricyclic diterpenoids.Chapter 3. First total synthesis of Mansonone P and RThe definition of Mansonone compounds were introduced in brief. An asymmetric total synthesis of Mansonone P and R was achieved. The synthesis highlights an OH substituent at position 2 by Sharpless dihydroxylation of silyl enol ether.Chapter 4. A Facile Synthesis of (S)-(-)-4-tert-Butyldimethylsiloxy-cyclopenten-l-oneThe application and syntheis reports for (S)-(-)-4-tert-Butyldimethylsiloxy-cyclopenten-1-one were introduced briefly. By using linchpin-coupling protocol construct the five membered ring as key step, a facile and efficient synthesis of the title compound, a key synthon used in natural product synthesis was described.