ENANTIOSELECTIVE ORGANOCATALYTIC CONJUGATE ADDITION FOR THE SYNTHESIS OF δ-SUBSTITUTED CYCLOHEXENONES AND ACYCLIC QUATERNARY ALL-CARBON CENTERS

Date
2023-12
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Abstract

Organocatalyzed reactions have become prominent in the synthesis of natural products, pharmaceutical drugs, and other industrially useful materials in the last few decades. 2,2-Bi-1-naphthol (BINOL) and its derivatives are unnatural chiral diol organocatalysts which have been used in many enantioselective reactions. For instance, Chong, Schaus, Goodman, and our group found that a BINOL catalyst with electron-withdrawing substituents enhanced reactivity with organoboronate nucleophiles to afford chiral products. First two chapters on this dissertation are to further explore the utility of an asymmetric BINOL catalyzed tandem reaction: (1) Conjugate addition and aldol condensation to synthesize δ-substituted cyclohexenones and (2) Synthesis of acyclic quaternary centers. The third chapter is mainly focused on the synthesis of tertiary boron compounds via photo-induced activation to tosylhydrazone. The formal Barluenga-Valdes coupling was developed decades ago. Under thermal conditions, the C-B bond is typically cleavage from the organoboronate product. Instead, this chapter is exploring the exploitation of this intermediate by using photoactivation conditions.

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Keywords
asymmetric synthesis:all-carbon quaternary center, conjugate addition, cyclohexenone
Citation
Portions of this document appear in: Peng, Po-Kai, and Jeremy A. May. "Enantioselective Organocatalytic Conjugate Addition in a Tandem Synthesis of δ-Substituted Cyclohexenones and Four-Step Total Synthesis of Penienone." Organic Letters 24, no. 29 (2022): 5334-5338; and in: Luo, Jirong, and Jeremy A. May. "Enantioselective Total Synthesis of Cannabinoids via a Tandem Conjugate Addition/Enolate Alkylation Annulation with Ambiphilic Organoboronates." Organic Letters 25, no. 4 (2023): 708-713.