Sciencemadness Discussion Board

addition to alkenes

puzzledstudent - 5-11-2006 at 12:17

hello. i'm back. thank you to drunkguy who has given great help in the past. i again need help with homework regarding addition to alkenes. just to let you all know, this is homework 8 of 10. so there'll be 2 more homeworks on which i will ask for double-checking. anyone, please be so kind as to check my answers. my answers and links to the homework follow:

page 1:
http://img.villagephotos.com/p/2006-10/1223233/ochemhw8p1.JP...

page 2:
http://img.villagephotos.com/p/2006-10/1223233/ochemhw8p2.JP...

My answers:
1-B
2-B
3-A
4-A
5-A
6-A
7-B
8-A
9-D

guy - 5-11-2006 at 12:46

2 - A, markinokov rule
9 - C?

Drunkguy - 5-11-2006 at 15:47

1. Hydroboration - anti Markovnikov (opposite from oxymercuration)

2. (b) Tertiary carbocation intermediate is stabilized

6. (a) seems obvious enough except that the carbocation will tend to undergo a 1,2-hydride shift so it's actually (b).

8. This is weird. I agree that (a) seems correct.

9. (c) Alkenes are hydrolyzed by aqueous acid.

[Edited on 6-11-2006 by Drunkguy]

Sandmeyer - 5-11-2006 at 16:05

Please, homework help is intended for Beginings Forum -- post there!

:mad:

guy - 5-11-2006 at 18:06

Quote:
Originally posted by Drunkguy
Actually, 4 is (b).


Why would 4 be B? It would be a straight molecule in a plane and according the markinokov rule it will only have one isomer.

Nicodem - 6-11-2006 at 03:20

4 is C.
The resulting compound, 3-bromo-3-methylpentane, is "an achiral compound". Thus the answer can not be neither B nor A, much less D. The confusion obviously arises from the lack of the insight that the addition creates symmetry around the prochiral site (another Et group forms, undistinguishable from the existing).

Sandmeyer - 6-11-2006 at 20:49

Damn, I wish I went to scool in America, they actually provide you answers on the tests - cool!

guy - 6-11-2006 at 20:53

Quote:
Originally posted by Sandmeyer
Damn, I wish I went to scool in America, they actually provide you answers on the tests - cool!


America does the worst in science! Probably because of religious fundamentalism.

dapper - 8-11-2006 at 20:37

or because we cheated all through general and organic chemistry.