Total Syntheses of Alanenses A, B, and Lacinilene E
Young Eum Hyun1, Chungwoo Lee1,2, Sunkyu Han1,2
1Department of Chemistry, Korea Advanced Institute of Science & Technology (KAIST), Daejeon 34141, Republic of Korea.
Abstract:
We achieved the total syntheses of (±)-alanenses A, B, and lacinilene E using a unified strategy based on α-N-phthalimido-oxy isobutyrate (NPIB)-mediated deoxygenative C-C bond formation. Key improvements to McCormick's route to (±)-lacinilene C7-methyl ether enabled scalable access to common intermediates, while a streamlined de novo approach further enhanced the efficiency of the synthetic route. Importantly, a late-stage sequence of reductions, 9-I-9-BBN-mediated bis-demethylation, and DDQ oxidation overcame the previously encountered demethylation challenges to furnish the first synthetic sample of lacinilene E. This work demonstrates a convergent approach to cadinane sesquiterpenoids and showcases the versatility of NPIB-based chemistry.
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