[SaKu]

Hello,

I'm making the Simmons Smith Reaction in lab, but it's not working at all... I found following article in this forum, and I have quite similiar problems:

citation:
Has anybody here done the Simmons-Smith, Furakawa modification (cyclopropanation of an alkene using Et2Zn, CH2I2, and TFA)?

This reaction is only working sporadically for me. I have been recovering starting material with just a bit of product. How big of an issue is oxygen in this reaction? Should I not see smoke when transferring diethylzinc to the round bottom? Is it OK to see a white precipitate when adding the CH2I2 to the diethylzinc, or should it just look cloudy?

BTW I do not have access to a glovebox or argon...

Any advice with this reaction would be greatly appreciated!!!!

end of citation


I'm already relieved that I'm not the only one having these problems. I already changed any conditions which are just possible, but without success...
Can anybody help?
Thanks in advance

[Alwin Kristen]

I have to say that im not experienced with simmons- smith reaction, but i found from literature that you would need a directing group (hydroxyl etc.) to get the reaction going. Also ultrasonication could improve your yield, because it improves the rate of formation of organozink compounds which mostlikely is the keyreagent for the reaction. If you dont have directing group present, you could try to dope your organozink reagent with some electron withdrawing group. That could get the reaction going without directing group. Also I found that the refluxion times were over 20h in most of the cases. Maybe if you just reflux it long enough you can get the reaction going.

Just ideas... just ideas...