1174445-86-3Relevant academic research and scientific papers
Enantioselective route to -silyl - Keto esters by organocatalyzed regioselective Michael addition of methyl ketones to a (silylmethylene)malonate and their use in natural product synthesis
Chowdhury, Raghunath,Ghosh, Sunil K.
experimental part, p. 1936 - 1945 (2011/07/31)
The direct Michael addition of alkyl methyl ketones through the acetyl methyl terminal to diethyl {[dimethyl(phenyl)silyl]methylene}malonate was catalyzed by the (S)-N-(pyrrolidin-2-ylmethyl)pyrrolidine/trifluoroacetic acid combination with high yield and excellent regio- and enantioselectivity. The ketone adducts can easily undergo de-ethoxycarbonylation to give β-silyl-δ keto esters with excellent synthetic potential. This has been demonstrated by the synthesis of a suitably substituted β-silyl-δ ester as an advanced intermediate for a chiral hydroxylated pyrrolidine natural product, (+)-preussin. Silicon-controlled diastereoselective reduction of the ketone functionality of β-silyl- δesters followed by lactonization of the resulting hydroxy esters gave disubstituted -valerolactones. Advanced intermediates for the antipodes of natural products, namely (+)-massoialactone and (+)-mevinolin analogue, and natural products, namely (-)-tetrahydrolipstatin and (+)-5-hexadecanolide, have been achieved. Georg Thieme Verlag Stuttgart - New York.
Highly regio- and enantioselective organocatalytic conjugate addition of alkyl methyl ketones TO A β-silylmethylene malonate
Chowdhury, Raghunath,Ghosh, Sunil K.
supporting information; experimental part, p. 3270 - 3273 (2009/12/01)
(S)-N-(2-Pyrrolidinylmethyl)pyrrolidine/trifluoroacetic acid (3:1) combination catalyzed the direct addition of alkyl methyl ketones to β-dimethyl(phenyl)silylmethylene malonate at the methyl terminal with high yield and excellent regio- and enantioselectivity. The silyl group played crucial roles in regioselection and substrate reactivity.
