Premium
Herstellung von erythro ‐2‐Hydroxybernsteinsäure‐Derivaten aus Äpfelsäureester. Vorläufige Mitteilung
Author(s) -
Seebach Dieter,
Wasmuth Daniel
Publication year - 1980
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.19800630118
Subject(s) - chemistry , alkylation , diastereomer , enantiomer , deprotonation , alkoxide , malic acid , derivative (finance) , stereochemistry , medicinal chemistry , organic chemistry , catalysis , citric acid , ion , financial economics , economics
Preparation for erythro ‐2‐Hydroxy‐succinic Acid Derivatives from Malic Esters As a contribution to the much discussed diastereoselective synthesis of enantiomers of open chain compounds, > 90% erythro ‐selective branching of malic esters by alkylation of the doubly deprotonated derivative 2 (alkoxide‐enolate) with methyl, allyl, and benzyl halides in THF at −78° (→ 3aa, 3ba, 3bb, 3bc , Table 1 ) is described. A second alkylation (→ 4 ) and addition of 2 to acetone (→ 5 ) are also possible. Cyclization of 2 to the enantiomerically pure trans ‐epoxides 6 is achieved by treatment with iodine. Cuprate opening of 6b furnishes the same product 3ba obtained from the methylation of 2b , establishing the configurational assignment.