Expedient Approach to 6‐Bromo‐2‐isopropylidenecoumaranone, a Potential Intermediate for the Synthesis of TMC‐120B, Pseudodeflectusin, and Their Congeners

2016/04/10 by Jorgelina L. Pergomet, Teodoro S. Kaufman, Andrea B. J. Bracca
Biochemistry, Genetics and Molecular Biology · Medicine · #Marine Sponges and Natural Products #Traditional and Medicinal Uses of Annonaceae #Synthesis of Organic Compounds

paper · doi:10.1002/hlca.201500525

Abstract

A straightforward approach toward 6‐bromo‐2‐isopropylidenecoumaranone, a potential intermediate toward alkaloid TMC 120‐B, pseudodeflectusin, and other natural products, was reported. The synthetic sequence involved the reaction of 3‐bromosalicylaldehyde with chloroacetone and cyclization of the resulting ether to a 2‐acetylcoumaranol intermediate. This was followed by sequential methyl Grignard addition and Jones ’ oxidation to the corresponding coumaranone, which was dehydrated to the final product with the methanesulfonyl chloride/pyridine reagent. The protection of the coumaranol as the corresponding THP‐ether resulted in improved product yields.

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