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Diastereo‐ und enantioselektive Synthese 1,2‐ trans ‐substituierter Cycloalkancarbonsäureester und Sulfone durch Michael‐initiierte Cyclisierungen via SAMP‐/RAMP‐Hydrazone [1,2]
Author(s) -
Enders Dieter,
Scherer Hermann J.,
Runsink Jan
Publication year - 1993
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19931260825
Subject(s) - chemistry , hydrazone , ketone , cyclopentanone , sulfone , stereocenter , michael reaction , diastereomer , stereochemistry , enone , enantiomer , enantioselective synthesis , organic chemistry , catalysis
Diastereo‐ and Enantioselective Synthesis of 1,2‐ trans ‐substituted Cycloalkanecarboxylates and Sulfones by Michael‐Initiated Cyclisation via SAMP / RAMP Hydrazones [1,2] An efficient and flexible synthesis of 1,2‐ trans ‐substituted cycloalkanecarboxylates and sulfones of high diastereo‐ and enantiomeric purity is described. The key step of the procedure is a Michael‐initiated ring closure (MIRC) reaction employing the SAMP/RAMP hydrazone method. Depending on the chain length of the ω‐bromo(iodo)enoates 2, 3 and the type of ketone SAMP‐hydrazone 1 , 3‐, 5‐, 6‐ and 7‐membered cycloalkane‐carboxylates 4–7 or cyclopentanesulfones 24 bearing two or three stereogenic centers are formed with very high asymmetric induction. In the same manner, MIRC reactions with ω‐(ethoxycarbonyl)enoate 26 give rise to 3‐substituted cyclopentanone‐2‐carboxylates 27 , but with lower overall chemical yields. The relative and absolute configurations are based on X‐ray structure analyses, spectroscopic and mechanistic investigations.