[Sharan]

Hey guys I have come across few synthesis problems and one of which is as follows:

what is most efficient method of synthesizing methylcyclopentane from cyclopentanone and any other organic or inorganic reagants in fewest number of steps/ It seems so simple but but I cant get through the last steps I mean it just doesn't finish :S I need *delete me*!

[miraculix]

Hi Sharan,

ever thought about Wittig-Olefination and subsequent hydrogenation of the olefin? Would be the most practical procedure in my humble opinion.

regards

miraculix

[agrobert]

Controlled methylation of the alpha carbon followed by reduction of the ketone.

[sjb]

As others have said, there are various ways. It may all come down to how you're interpreting "most efficient" - how about 1,2-addition of something like 1,2-addition of MeLi to form the alkoxide, then work-up with strong acid to firstly form alcohol then dehydrate and form 1-methylcyclopentene, then reduce the double bond with e.g. diimide?

S

[loveshack321]

CHM140Y5 eh? Yea  was doing that one and it IS simple. really just do it slowly and constantly check your functional groups. If you want I can outline it for you using a chem software i have that allows me to make molecules. send me your UTOR email id and ill send it over. good luck studying bye!

[sjb]

If you want I can outline it for you using a chem software i have that allows me to make molecules.

Damn (excuse my French), there go the employment stats. I assume hope you mean software that allows you to draw molecules, or things like SciFinder that allow searches for conditions and papers.

(Though in a few years time, who knows. Look into Gasteiger and Hendrikson's work  - there are others too, but I don't recall their names)

[loveshack321]

I apologize for my incorrect statement. it allows me to draw molecules not show me how to make them. the driving force behind how to make them has to come from you. It does indeed show tell you though for incorrect valence etc as to monitoring your work as you synthesize. kind of like spell checker. the name of the program is by the way Chemoffice 2008.

[cubane]

1. Strong base (LDA)
2. Methyl Halide (ClCH3)
3. Reducing Agent (LAH)
4. Elimination of -OH (H2SO4/Heat)
5. Hydrogenation of an Alkene (H2/Pt)

[macman104]

1. Strong base (LDA)
2. Methyl Halide (ClCH3)
3. Reducing Agent (LAH)
4. Elimination of -OH (H2SO4/Heat)
5. Hydrogenation of an Alkene (H2/Pt)

You could condense steps 3-5 with a Clemmensen Reduction.  But as other's have pointed out above, the shortest strategy would be wittig olefination, followed by hydrogenation of the double bond.

[g-bones]

Hi Sharan,

ever thought about Wittig-Olefination and subsequent hydrogenation of the olefin? Would be the most practical procedure in my humble opinion.

regards

miraculix

Good Ideal! Pd/C under H2 pressure or wilkinson's catalyst under H2 pressure or (if you want to overreact lol) you can use crabtrees catalyst under H2 pressure to hydrogenate