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The stereoselectivity of michael additions leading to enantiomerically pure indoloquinolizidones
Author(s) -
Peng Shiqi,
Winterfeldt Ekkehard
Publication year - 1990
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.199019900160
Subject(s) - chemistry , diketene , stereoselectivity , oxalic acid , diastereomer , malonate , yield (engineering) , acylation , michael reaction , derivative (finance) , acetal , stereochemistry , organic chemistry , medicinal chemistry , catalysis , materials science , economics , financial economics , metallurgy
Acylation of the carboline derivatives 6 and 9 with diketene affords the corresponding N ‐(acetoacetyl)carbolines 7 and 10 , respectively. While 10 can be converted into a 1:2.1 mixture of the title compounds 11 a and 11 b on treatment with oxalic acid, the cyclic acetal 7 can only be cyclized to yield the pyridone derivative 8 . Michael addition of methyl malonate to the unsaturated ketone 11 b proceeds with excellent stereoselectivity to generate the keto diester 12 a which, on treatment with a base is transformed into its diastereoisomer 12 b . In contrast to 11 b , its stereoisomer 11 a does not react with methyl malonate.