Enantioselective mukaiyama-michael reactions of 2-carbomethoxy cyclopentenone catalyzed by chiral bis(Oxazoline)-Cu(II) complexes
作者:Anna Bernardi、Giorgio Colombo、Carlo Scolastico
DOI:10.1016/s0040-4039(96)02048-5
日期:1996.12
addition of propionate silylketene acelal 1 to 2-carbomethoxy cyclopentenone is promoted by bis(oxazoline)-Cu(II) complexes with high diastereoselectivity and good enantiomeric excesses. The absolute configuration of the product can be controlled by varying the copper counterion. A catalytic version of the reaction was developed, which gave ketoacid 5a in 72% d.e. and 63% e.e.
The conjugate addition of t-butylpropionate silylketeneacetal 2 to 2-carboxycyclopentenones 3a-b promoted by TADDOL-derived Ti chlorides gives the ketoacid 6 with excellent d.e. and e.e. up to 47%.
Influence de la substitution en 1 sur la stereoselectivite de l'hydrolyse de N,N diethylamino-7 dialkyl-1,6 bicyclo (3,2,0) heptene-6 ones-2 ; une nouvelle voie d'acces au controle des centres C17 et C20 de steroides
作者:D Desmaële、J Ficini、A Guingant、Ph Kahn
DOI:10.1016/s0040-4039(00)88100-9
日期:1983.1
We report on the stereocontrolled hydrolysis (5 % HCO2H) of enamines 4(R1 ≠ H) leading to keto-acids 6 and describe the synthesis of cyclopentanones 2 which can be envisioned as intermediates in the total synthesis of vitamine D3 and its metabolites.