[nikienikie]

Hi,

I am confused with this problem:

"Write the expected product from the reaction of cis-2-pentene with aqueous chlorine."

I know the mechanism and understand that the Cl and OH addition has to be anti but I do not know how to show all the stereo-isomers. How do I know where to put dashes and where to put wedges?

Thank you!

[rrr_asd]

An electrophilic addition reaction is stereospecific: http://en.wikipedia.org/wiki/Dihalo_addition_reaction

[camptzak]

correct me if im wrong but wouldnt the compound shown spontaneously form an epoxide. which would then be attacked by a water molecule to form a a diol?

also couldnt this compound undergo some hydride shifts, and form a diol at different points?

[discodermolide]

correct me if im wrong but wouldnt the compound shown spontaneously form an epoxide. which would then be attacked by a water molecule to form a a diol?

also couldnt this compound undergo some hydride shifts, and form a diol at different points?

As shown, I don't think they will form an epoxide as the HO and Cl and not anti to one another as drawn. I need to make a model.
What the answer misses are the other addition pairs where the OH and Cl are interchanged.

[orgopete]

correct me if im wrong but wouldnt the compound shown spontaneously form an epoxide.

A chlorohydrin (chloro alcohol) can form an epoxide if the alcohol is converted to an alkoxide. The by-product of the chlorination is HCl. That will suppress epoxide formation.

[PhDoc]

Alkenes react with halogens (Cl2, Br2) in aqueous media to form cyclic halonium ions that are opened stereospecifically, affording anti halohydrins. There are no epoxides involved unless the ISOLATED compound is treated with strong base such as NaOH, NaOMe (both nucleophilic) or NaH (non-nucleophilic). Please keep in mind there is continuous freedom of rotation about carbon-carbon single bonds. Any halohydrin by virtue of its stereospecific formation will have a hydroxyl and a halogen anti to one another.