The Hive => Methods Discourse => Topic started by: tropine on December 15, 2003, 06:40:00 AM
Title: How to reduce C=C to C-C
Post by: tropine on December 15, 2003, 06:40:00 AM
Thiking of using Li in ammonia to reduce the double bond in 2,5-dimethoxy-2,5 dihydrofuran, any comments? I want to avoid Raney Nickel as it is pyrrophoric!
Title: And Lithium isn't?
Post by: Rhodium on December 15, 2003, 10:58:00 AM
And Lithium isn't?
Title: Dimethoxytetrahydrofuran
Post by: roger2003 on December 15, 2003, 04:38:00 PM
If you read this JACS -Article, I think, you know more
Post 458701 (https://www.thevespiary.org/talk/index.php?topic=9211.msg45870100#msg45870100)
(Rhodium: "2,5-Dimethoxy-tetrahydrofuran from Furan", Methods Discourse)
Title: The JACS article is about RAney Nickel again
Post by: tropine on December 16, 2003, 06:50:00 AM
thanks for the link, but the JACS article just talks about Raney Nickel again. Yes Lithium is pyrrophoric, but I thought that Li in liquid ammonia is much less dangerous than Raney Nickel in H2, do you have any experience with Raney Nickel?
Title: the pressure is the most dangerous part
Post by: Rhodium on December 16, 2003, 07:05:00 AM
I thought that Li in liquid ammonia is much less dangerous than Raney Nickel in H2
I would say the other way around, as long as you have equipment which can take the necessary pressure.
Title: 2000 psi is not an option for any sane bee
Post by: tropine on December 16, 2003, 08:58:00 AM
those pressures are just too high for my comfort zone. The Li in ammonia is well documented on your site rhod, for the reduction of ephedrine. Mr. Clean's writeup it pretty good, and all precautions are noted. Chemically however do you think that the reduction will work on the dimethoxydihydrofuran C=C double bond? I am quite sure it will...no pressure and flammable gas, looks like a safer approach to me!
Title: dimethoxytetrahydrofuran
Post by: roger2003 on December 16, 2003, 11:12:00 AM
If you carry out the reduction (or the workup) in aqueous solutions the dimethoxy converts to dihydroxy.
I read this a lot of years ago and cannot find again now.