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3‐Lithiopyrroles by Halogen‐Metal Interchange of 3‐Bromo‐1‐(triissopropylsilyl)pyrroles. Synthesis of Verucarin E and Other 3‐Substituted Pyrroles. Preliminary Communication
Author(s) -
Muchowski Joseph M.,
Naef Reto
Publication year - 1984
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.19840670430
Subject(s) - chemistry , pyrrole , halogen , electrophile , trimethylsilyl , reagent , lithium (medication) , fluoride , bromine , medicinal chemistry , combinatorial chemistry , organic chemistry , inorganic chemistry , catalysis , endocrinology , medicine , alkyl
3‐Lithio‐1‐(trimethylsilyl)pyrrole ( 7 , Schem 2 ), obtained by halogen‐metal interchange from the 3‐bromo compound 2 , reacted with various electrophilic reagents to provide products, which on fluoride ion desilylation, gave 3‐substituted pyrroles in good overall yields. One such pyrrole 13 ( Schem 3 ), was converted into 2‐formyl‐3‐octadeclpyrrole ( 14 ), reputed to be a metabolite of the marine sponge Oscarella lobularis . 3,4‐Dibromo‐1‐(triisopropylsityl)pyrrole ( 5 ) was efficiently transformed, by a process involving two consecutive bromine‐lithium exchange reactions ( Scheme 4 ), into the antibiotic verrucarin E 17 .