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Asymmetric Synthesis via Heterocyclic Intermediates, XLVII. Asymmetric Synthesis of (+)‐(1 R ,2 S )‐ allo ‐Coronamic Acid
Author(s) -
Groth Ulrich,
Halfbrodt Wolfgang,
Schöllkopf Ulrich
Publication year - 1992
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.199219920162
Subject(s) - chemistry , yield (engineering) , alkylation , intramolecular force , lithium (medication) , allylic rearrangement , tsuji–trost reaction , stereochemistry , chloride , medicinal chemistry , organic chemistry , catalysis , medicine , materials science , metallurgy , endocrinology
allo ‐Coronamic acid ( 1 ) was synthesized in five steps enantiomerically and diastereomerically virtually pure by starting from the bislactim ethers of cyclo(‐ L ‐Val‐Gly‐) ( 3a ) or cyclo‐(‐ L ‐ tert ‐Leu‐Gly‐) ( 3b ) in an overall yield of 31%. The key step of this synthesis is the intramolecular alkylation of the lithium azaenolate derived from the allylic chloride 4 .