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The first catalytic method for diastereo- and enantioselective synthesis of allylic boronates bearing a Z-trisubstituted alkenyl fluoride is disclosed. Boryl substitution is performed with either a Z- or E-allyldifluoride and is catalyzed by bisphosphine/Cu complexes, affording products in up to 99 % yield with >98:2 Z/E selectivity and 99:1 enantiomeric ratio. A variety of subsequent modifications are feasible, and notable examples are diastereoselective additions to aldehydes/aldimines to access homoallylic alcohols/amines containing a fluorosubstituted stereogenic quaternary center.

A major shortcoming in olefin metathesis, a chemical process that is central to research in several branches of chemistry, is the lack of efficient methods that kinetically favor E isomers in the product distribution. Here we show that kinetically E-selective cross-metathesis reactions may be designed to generate thermodynamically disfavored alkenyl chlorides and fluorides in high yield and with exceptional stereoselectivity. With 1.0 to 5.0 mole % of a molybdenum-based catalyst, which may be delivered in the form of air- and moisture-stable paraffin pellets, reactions typically proceed to completion within 4 hours at ambient temperature. Many isomerically pure E-alkenyl chlorides, applicable to catalytic cross-coupling transformations and found in biologically active entities, thus become easily and directly accessible. Similarly, E-alkenyl fluorides can be synthesized from simpler compounds or more complex molecules., National Institutes of Health (U.S.) (grant GM-59426)

A major shortcoming in olefin metathesis, a chemical process that is central to research in several branches of chemistry, is the lack of efficient methods that kinetically favor E isomers in the product distribution. Here we show that kinetically E-selective cross-metathesis reactions may be designed to generate thermodynamically disfavored alkenyl chlorides and fluorides in high yield and with exceptional stereoselectivity. With 1.0 to 5.0 mole % of a molybdenum-based catalyst, which may be delivered in the form of air- and moisture-stable paraffin pellets, reactions typically proceed to completion within 4 hours at ambient temperature. Many isomerically pure E-alkenyl chlorides, applicable to catalytic cross-coupling transformations and found in biologically active entities, thus become easily and directly accessible. Similarly, E-alkenyl fluorides can be synthesized from simpler compounds or more complex molecules.

The amphidinolides are macrolide natural products isolated from marine dinoflagellates of the genus Amphidinium and most of them display potent cytotoxic activities in vitro. Amphidinolides C-C3, F and T1-5 represent attractive synthetic targets due to a combination of potent bioactivity and complex molecular architecture. This thesis describes the total syntheses of amphidinolides T1, T3 and T4, and the preparation of the C1-C17 fragment of amphidinolides C and F. Concise and high-yielding total syntheses of amphidinolides T1, T3, and T4 have been completed using an alkynyl macrolactone as a common late-stage intermediate. The α-hydroxy ketone motif was installed by sequential alkyne hydrosilylation, epoxidation, and Fleming–Tamao oxidation. A tandem oxonium ylide formation [2,3]-sigmatropic rearrangement reaction was used to construct the trisubstituted tetrahydrofuran core found within the natural products. The C1-C17 fragment of amphidinolides C, C2, C3 and F was synthesised employing [2,3]-sigmatropic rearrangement of an oxonium ylide generated by decomposition of 1-sulfonyl-triazole to construct the trisubstituted tetrahydrofuran ring found in the natural products. The two main segments were conjoined using a Stille cross-coupling reaction that allowed simultaneous installation of the isomerization-prone 1,3-diene unit.