| Three zirconocene dichlorides were synthesized in a short sequence and in relatively high overall yield (25–56%). In situ hydrozirconation of 1-, 2-, and 4-octene was carried out in the presence of stoichiometric Super-hydride. The substituent on the Cp ring changed the solubility and the reactivity of two new zirconocene dihydrides, leading to novel inter- and intramolecular coupling reactions of unsaturated substrates.; The Diels-Alder reaction of acyl-1,3-oxazolidin-2-one with trans -1-N-acylamino-1,3-diene catalyzed by chiral Lewis acid was investigated. The Diels-Alder adducts were obtained with high endo/exo selectivity and in good yields. The enantioselectivities were moderate to good. Furthermore, recrystallization led to a significant increase in the enantiomeric excess. MacMillan's organic base was also effective as a catalyst for this transformation. The Diels-Alder reaction between a fumarate derivative and 1,3-butadiene followed by a Curtius rearrangement provided an efficient way to prepare trans-β-amino acid derivatives.; Three new highly functionalized β-amino acid building blocks were prepared for the solid phase synthesis of water-soluble β-peptide foldamers. (1R,3S,4S,6R)-6-(9 H-Fluoren-9-ylmethoxycarbonylamino)-2,2-dimethylhexahydrobenzo[1,3]dioxole-5-carboxylic acid was successfully applied for the preparation of a dodecamer.; A series of pseudo-C2 symmetric bidentate ligands were successfully designed and synthesized. The use of the ligand (1R,2R)-N-[2-(4-isopropyl-4,5-dihydrooxazol-2-yl)cyclohexyl]methane sulfonamide in the catalytic asymmetric addition of Et2Zn to aldehydes led to good enantioselectivity with low catalyst loadings and validated the efficacy of this type of ligand for asymmetric catalysis.; A new, efficient, and more general methodology for the synthesis of oxazolines and thiazolines in the presence of catalytic amounts of arylboronic acid was developed. The reaction worked particularly well for the parallel synthesis of a 4 x 6 combinatorial library of oxazolines and thiazolines. A total of 17 oxazolines and 6 thiazolines were obtained from 24 reactions. Most yields ranged between 40% to 100% and were comparable or better than in the traditional reaction setup. The purities exceeded 82% in each case as determined by GC-MS analysis.; Two synthetic routes were developed for the total synthesis of the Pulveroboletus ravenelii lactones. The first route failed due to the low reactivity of 1,2-diphenyl-substituted enoates toward Michael addition. The second route applies a key Claisen rearrangement reaction and is still under investigation. |
