<p> Transition-metal catalyzed cross-coupling has, in many ways, revolutionized synthetic chemistry by providing streamlined syntheses using highly modular building blocks. Despite the widespread application of the Suzuki and Buchwald-Hartwig cross-coupling reactions, utilization of more contemporary cross-coupling protocols is narrower. Progress in applied research using transition- metal catalyzed reactions is often hampered by the necessity for unwieldy substrate syntheses. Seeking to tackle this problem, we have developed two novel C-C bond forming reactions in the context of the oxidative boron Heck reaction that converts simple starting materials into highly useful products which are directly applicable to many powerful synthetic protocols. </p><p> Firstly, an aerobic boron Heck reaction has been developed, which facilitates the conversion of feedstock olefins, namely, ethylene and propylene to styrenes and b-methylstyrenes using abundant (hetero)aryl boronic acids. The relevance to complex molecule synthesis is highlighted by a two-step synthesis of the pharmaceutical phenprocoumon. </p><p> Secondly, an aerobic boron Heck reaction of cyclobutene has been developed using abundant (hetero)aryl boronic acids. Instead of forming the classical Heck product (3-aryl-cyclobutene) a linear 1-aryl-1,3-diene is generated with complete chemo-, regio- and stereo-selectivity. 1-Aryl- 1,3-dienes have found myriad applications in modern transition-metal catalyzed cross-couplings however the substrates are often prepared by poorly efficient Wittig reactions. Both computational and mechanistic experimental data support a mechanism that proceeds by a classical Heck reaction followed by pericyclic ring opening mechanism for C-C bond cleavage. 1-Aryl-1,3,5-trienes were similarly prepared using alkenyl boronic acids.</p><p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:10977124 |
| Date | 20 December 2018 |
| Creators | McAlpine, Neil James |
| Publisher | Princeton University |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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