The development and applications of geminal acylation

The research presented in this thesis is focused on three areas of synthesis with geminal acylation as a central theme.;The first area is the development of the geminal acylation process with the acetals of aldehydes. The procedures in the literature that employ ketone acetals failed to give any geminally acylated product. A variety of acetals derived from aldehydes reacted with 1,2-bis(trimethylsilyloxy)cyclobutene in the presence of boron trifluoride etherate, and then treatment with Amberlyst 15 resin in trifluoroacetic acid provided the desired 1,3-cyclopentanedione products. A vicinally disubstituted analogue of the cyclobutene reacted in a similar manner, but reactions with 3,3-dimethyl-1,2-bis(trimethylsilyloxy)cyclobutene yielded 1,2-cyclopentanediones with modest yields. Using 1,2-bis(trimethylsilyloxy)cyclopentene under the same conditions followed a third reaction pathway, to give 1,2-cyclopentanediones. This pathway is proposed to involve a unusual mechanism: the 1,3-transposition of an hydroxyl group and a double bond with the enol of a ketone serving as the double-bond.;The second area of investigation employed a double geminal acylation for the production of 5-X-5 tricyclic ring systems. Addition of a second tether to the bis(1,3-cyclopentanedione) derivative should form the 5-X-5 tricyclic ring systems. Attempts to add the tether were unsuccessful, but ultimately [5.16.5] and [5.17.5] tricyclic ring systems were prepared via double Heck reactions with 1,7-octadiene and 1,8-nonadiene. An unprecedented pentacyclic system with a large central ring was produced via ruthenium-mediated metathesis.;The third area of research involved assembling unsaturated spirocyclic diketones using geminal acylation, adding two unsaturated chains to the carbonyl groups, and carrying out ruthenium-mediated relayed metathesis reactions to produce a variety of angular tricyclic compounds. This work demonstrated that a cyclohexene moiety can serve as a relaying alkene in an efficient manner, contrary to recent reports. Substrates with both cis and trans alkene chains gave the tricyclic compounds in good yields, and substrates with cis alkene chains provided none of the products of direct intramolecular metathesis, i.e., not relayed. The different reacting geometries of allyl and butenyl chains produced only one major product. In contrast, utilization of a cycloheptene moiety as the relaying alkene worked only modestly, and intermolecular metathesis reactions gave significant amount of products.