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Expedient Approach to 6‐Bromo‐2‐isopropylidenecoumaranone, a Potential Intermediate for the Synthesis of TMC‐120B, Pseudodeflectusin, and Their Congeners
Author(s) -
Pergomet Jorgelina L.,
Kaufman Teodoro S.,
Bracca Andrea B. J.
Publication year - 2016
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201500525
Subject(s) - chemistry , natural product , pyridine , reagent , ether , chloride , stereochemistry , grignard reagent , alkaloid , total synthesis , organic chemistry , combinatorial chemistry
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.