Making alkenes throu grignard reaction

[Maria_88]

Hi I am taking a summer course in organic chermisty and I need to make the following alkenes through a grignard reaction.

 

5-methyl-1-hexene

2,5,5-trimethyl-2-heptene

 

How do i go about to do this?

 

I'm sure i could find the answed in my textbook, but since it wasnt in stock at the book store i have'nt gotten it yet.

 

Thanx in advance

Maria

[Horza2002]

Im not sure about using Grignards to make alkenes....there are easier ways to alkenes than using them...my guess eold be to have formaldehyde and treat that with 4-methyl pentant-1-magnesium bromide and then treating this with a strong acid to eliminate water generating the alkene