215033-01-5Relevant academic research and scientific papers
Allylsilyl propargyl ethers as substrates for intramolecular Pauson-Khand reactions
Ishaq, Salma,Porter, Michael J.
, p. 547 - 557 (2006)
Silyl ethers that are synthesized by coupling a propargylic alcohol with an allylsilyl chloride are shown to undergo sulfide-promoted Pauson-Khand reactions, affording bicyclic enones. Copyright Taylor & Francis Group, LLC.
Stereocontrol in organic synthesis using silicon-containing compounds. A formal synthesis of prostaglandins controlling the stereochemistry at C-15 using a silyl-to-hydroxy conversion following a stereochemically convergent synthesis of an allylsilane
Fleming, Ian,Winter, Stephen B. D.
, p. 2687 - 2700 (2007/10/03)
Hydrosilylation of isoprene with chloro(diphenyl)silane gave (Z)-chloro(2-methylbut-2-enyl)-diphenylsilane 7. The cuprate reagent derived from this chloride underwent conjugate addition to methyl cinnamate 11, 1,2-silylcupration with hex-1-yne 16 and allene 18, and allylic displacement reactions with 1-vinylcyclohexyl acetate 20 and (Z)-1-cyclopentyloct-2-en-1-yl acetate 22. The silyl group in each of the products was converted into a hydroxy, with the removal of the 2-methylbut-2-enyl group taking place under much milder acidic conditions than those needed to remove the phenyl group from the dimethyl(phenyl)silyl group, and making this group suitable for the conversion of an allylsilane into an allyl alcohol. A stereospecifically anti conjugate displacement of the allylic benzoate group in (Z)-(1S,5R,6R,7R,1′S)-7-benzoyloxy-6-(1′-benzoyloxyoct-2′- enyl)-2-oxabicyclo[3.3.0]octan-3-one 52, and a stereospecifically syn conjugate displacement of the carbamate group in (Z)-(1S,5R,6R,7R,1′R)-7-benzoyloxy-6-(1′-N-phenylcarbamoyloxyoct- 2′-enyl)-2-oxabicyclo[3.3.0]octan-3-one 51, gave stereo-convergently the same allylsilane (1′ E,2″Z)-(1S,5S,6R,7R,3′S)-7-benzoyloxy-6-[3′-(2″- methylbut-2″-enyl)-diphenylsilyloct-1′-enyl]-2-oxabicyclo[3.3.0] octan-3-one 53. Silyl-to-hydroxy conversion gave the allyl alcohol (E)-(1S,5S,6R,7R,3′S)-7-benzoyloxy-6-(3′-hydroxyoct-1′-enyl)- 2-oxabicyclo[3.3.0]octan-3-one 54, having the relative and absolute stereochemistry at C-15 of the prostaglandins.
A synthesis of (±)-lavandulol using a silyl-to-hydroxy conversion in the presence of 1,1-disubstituted and trisubstituted double bonds
Fleming, Ian,Lee, Duckhee
, p. 2701 - 2709 (2007/10/03)
Silylcuprates and silylzincates react with α,β-unsaturated aldehydes, esters, ketones and amides 19 unsubstituted at the β-position in higher yield if trimethylsilyl chloride is present. Applying this method, conjugate addition of the silylcuprate 26 derived from (Z)-chloro(2-methylbut-2-enyl)diphenylsilane 24, itself prepared by an improved route, to 3-methylene-6-methylhept-5-en-2-one 25 gave 3-[(Z)-2-methylbut-2-enyl(diphenyl)silyl]methyl-6-methylhept-5-en-2-one 27. A Wittig reaction gave 3-[(Z)-2-methylbut-2-enyl(diphenyl)silyl]methyl-2,6-dimethylhepta-1,5-diene 28 and silyl-to-hydroxy conversion gave lavandulol 1, even in the presence of the 1,1-disubstituted and trisubstituted double bonds. The hydroxy group of the 3-hydroxysilane, 2,6-dimethyl-3-{[(Z)-2-methylbut-2-enyl]diphenylsilyl}methylhept-5-en-2-ol 30, activated the allylsilane group towards protodesilylation. Chloro(diphenyl)methallylsilane 35 is easier to make than the chloride 24, and should be an alternative allylsilane that can make a lithium and hence a cuprate reagent like 26.
