Thesis

The total synthesis of (-)-Tatarinoid B and initial investigations into the catalytic 1,2-additions of allyl indium reagents to aldehydes

Thesis (M.S., Chemistry)--California State University, Sacramento, 2018.

This thesis examines two independent studies including the first enantioselective total synthesis of (-)-Tatarinoid B and investigations into developing an asymmetric catalytic 1,2-addition of allyl indium reagents to aldehydes. (-)-Tatarinoid B is one of 19 compounds that has been isolated from the rhizome of the plant Acorus tatarinowii. Commonly referred to as Acorus, this plant is widely used in Chinese medicine due to its pharmacological effects on the central nervous system and its ability to regulate cyclic adenosine monophosphate (cAMP) activity. (-)-Tatarinoid B was synthesized from 1-bromo-2,4,5-trimethoxybenzene in five steps and in greater than 99% ee and a 62% yield. In addition, the structural elucidation and a revision to absolute configurations of (-)-Tatarinoids A, B, and C are described and presented in this thesis. The second study presented herein is focused on investigating a novel enantioselective indium-mediated allylation of aldehydes to form secondary homoallylic alcohols using water as a co-solvent, non-toxic indium metal, and an inexpensive organic chiral reagent, thereby making this methodology an environmentally friendly and cost-effective alternative to the existing protocols. This approach would allow access to a wide range of useful homoallylic intermediates and would prove to be useful in natural product synthesis. The reaction was proven to be successful with a variety of activating and deactivating substituents yielding the desired secondary alcohols in good to quantitative yields (65% - 99%) with no rigorous reaction conditions needed.

This thesis examines two independent studies including the first enantioselective total synthesis of (-)-Tatarinoid B and investigations into developing an asymmetric catalytic 1,2-addition of allyl indium reagents to aldehydes. (-)-Tatarinoid B is one of 19 compounds that has been isolated from the rhizome of the plant Acorus tatarinowii. Commonly referred to as Acorus, this plant is widely used in Chinese medicine due to its pharmacological effects on the central nervous system and its ability to regulate cyclic adenosine monophosphate (cAMP) activity. (-)-Tatarinoid B was synthesized from 1-bromo-2,4,5-trimethoxybenzene in five steps and in greater than 99% ee and a 62% yield. In addition, the structural elucidation and a revision to absolute configurations of (-)-Tatarinoids A, B, and C are described and presented in this thesis. The second study presented herein is focused on investigating a novel enantioselective indium-mediated allylation of aldehydes to form secondary homoallylic alcohols using water as a co-solvent, non-toxic indium metal, and an inexpensive organic chiral reagent, thereby making this methodology an environmentally friendly and cost-effective alternative to the existing protocols. This approach would allow access to a wide range of useful homoallylic intermediates and would prove to be useful in natural product synthesis. The reaction was proven to be successful with a variety of activating and deactivating substituents yielding the desired secondary alcohols in good to quantitative yields (65% - 99%) with no rigorous reaction conditions needed.

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