[noork85]

im confused which method i should use to form the hoffman product double bond.

this is the original work. https://www.dropbox.com/s/iw784mtv0szp86d/2013-05-17%2020.30.46.jpg i basically want to eliminate the h-br and replace those steps with https://www.dropbox.com/s/gei4i2x2mnwimbj/2013-05-17%2020.31.04.jpg

will this work?? can i do a synthesis with a minir product if i used h2so4/heat to create the double bond? i know that gives a hoffman product thats minor.

[TheOrganic]

im confused which method i should use to form the hoffman product double bond.

this is the original work. https://www.dropbox.com/s/iw784mtv0szp86d/2013-05-17%2020.30.46.jpg i basically want to eliminate the h-br and replace those steps with https://www.dropbox.com/s/gei4i2x2mnwimbj/2013-05-17%2020.31.04.jpg

will this work?? can i do a synthesis with a minir product if i used h2so4/heat to create the double bond? i know that gives a hoffman product thats minor.

The replaced steps in the photo are ok.
But, I'm not sure whether I understand your second question. Are you asking if dehydrating an alcohol forms the hoffman product? If that is your question, what are the conditions that lead to formation of Hoffman product? Why does this less stable product form, sometimes? Is concentrated H₂SO₄ + heat a plausible condition for Hoffman product?

[noork85]

ok so h2so4 is going to give me the hoffman product as a minor product,not major. but can i proceed with a synthesis using a minor product? that would make the synthesis less effective, right?

[TheOrganic]

ok so h2so4 is going to give me the hoffman product as a minor product,not major. but can i proceed with a synthesis using a minor product? that would make the synthesis less effective, right?

It depends on how minor the products are. If the minor product is 40% and major is 60% , then sometimes we use it. But that's rarely.

In general you should avoid using the minor product for synthesis. You'll start with one mole of the original substance, and end up only a small fraction of a mole of final product! In short, yield is less if you use minor.

[noork85]

thanks....so the synthesis is okay???

[camptzak]

why not use chlorinated acetylaldehyde?

[noork85]

why not use chlorinated acetylaldehyde?

which step???