ring opening of epoxides with alcohols
play

RINGOPENING OF EPOXIDES WITH ALCOHOLS R H H C R O H + - PowerPoint PPT Presentation

RINGOPENING OF EPOXIDES WITH ALCOHOLS R H H C R O H + + H Nu Nu M M L L + N EWG N H H R R R + H H C O L: N, P : substrste H H this work OCH 3 OH O cat + CH 3 OH OH +


  1. RING–OPENING OF EPOXIDES WITH ALCOHOLS R H H C R δ – O H δ + δ + H Nu δ – Nu M M L L δ – δ – δ + N EWG N H H R R R δ + H H C O L: N, P : substrste H H this work OCH 3 OH O cat + CH 3 OH OH + OCH 3 R R R

  2. REACTION OF STYRENE OXIDE WITH METHANOL OH OCH 3 O OCH 3 OH cat + CH 3 OH + CH 3 OH 50 °C, 24 h A B epoxide:CH 3 OH:cat = 50:500:1 Ru cat: Ts product N N yield, % conv, % cat A:B Ru Ru N Cl N arene–Ru 50 29 90:10 H H 2 Cp*RuCl/KOH 31 31 82:18 arene–Ru complex Cp*RuCl complex KOH 82 33:67 97 Ts = p -CH 3 C 6 H 4 SO 2

  3. REACTION OF STYRENE OXIDE WITH ALCOHOLS OR OH Ru cat O OH + OR + ROH C 6 H 5 C 6 H 5 C 6 H 5 ROH 50 °C, 24 h A B epoxide:ROH:cat = 50:500:1 Ru cat: Ru[( S,S )-Tsdpen]( p -cymene) yield, % byproducts: ROH A B byproducts OH CH 3 OH 26 1 34 C 6 H 5 CH 3 CH 2 OH 22 1 25 OH (CH 3 ) 3 COH <1 <1 0 C 6 H 5

  4. LIMITATION O O C 6 H 5 C 6 H 5 reactive inert O O O C 6 H 5 inert inert

  5. REACTION OF rac -STYRENE OXIDE WITH METHANOL OH OCH 3 O OH OCH 3 * * ( S,S )-Ru cat + + CH 3 OH CH 3 OH 50 °C, 6 h A B 95:5 racemate 34% conv 20% yield epoxide:CH 3 OH:cat = 50:500:1 68% ee ( R ) ( S,S )-Ru cat: Ru[( S,S )-Tsdpen]( p -cymene) Ts C 6 H 5 N Ru N C 6 H 5 H

  6. REACTION OF ( S )-STYRENE OXIDE WITH METHANOL OCH 3 OH O OH OCH 3 S Ru cat R * + + CH 3 OH CH 3 OH 50 °C, 24 h >99% ee A B epoxide:CH 3 OH:cat = 50:500:1 recovered epoxide product (A) yield, % ee, % (config) yield, % ee, % (config) Ru cat Ru[( S,S )-Tsdpen]( p -cymene) 6 ( R ) 40 ( R ) 9 68 Ru[( R,R )-Tsdpen]( p -cymene) 97 ( S ) 76 ( R ) 58 31 Ru(Ts-en)( p -cymene) 95 ( S ) 63 ( R ) 67 27

  7. RACEMIZATION OF ( S )-STYRENE OXIDE O O chiral Ru cat S solvent 50 °C, 24 h epoxide:solvent:chiral cat = 50:500:1 recoverd epoxide yield, % ee, % (config) chiral Ru cat solvent chiral Ru cat: Ts CH 3 OH S,S 9 5 ( R ) C 6 H 5 N * R,R CH 3 OH 58 97 ( S ) Ru S,S (CH 3 ) 3 COH 95 14 ( R ) N C 6 H 5 * H (CH 3 ) 3 COH R,R 97 99 ( S ) S,S C 6 H 6 >99 57 ( R ) Ts = p -CH 3 C 6 H 4 SO 2 >99 20 ( R ) R,R C 6 H 6

  8. cis – trans ISOMERIZATION OF STILBENE OXIDE O O ( S , S )-Ru cat CH 3 OH 50 °C, 24 h 14% conv cis trans 14% yield 19% ee O O ( S , S )-Ru cat CH 3 OH 50 °C, 24 h cis (±)- trans no reaction epoxide:CH 3 OH:Ru= 50:500:1 ( S , S )-Ru cat: Ru[( S,S )-Tsdpen]( p -cymene)

  9. SUMMARY OCH 3 OCH 3 O[Ru] OH OH CH 3 OH CH 3 OH S R S N 2 S N 1 CH 3 OH O[Ru] O[Ru] R

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend


More recommend