in OMDM the addition of water takes place according marconikoff rule but shifting is not allowed...in HBO addition of water take place according to anti- marckonikoff rule( kharash effect)
alkenes react with mercuric acetate in the presemce of water 2 give hydroxy mercurial compounds which on reduction yields aclcohol. this is called OMDM reaction... OMDM is highly regioselective and gives alcohols corresponding to markownikoff addition 2 the carbon carbon double bond....
Hydroboration is carried out in an ether, commonly THF(tetra hyro furan or diglyme(di methyl glycol methyl ether) It gives products acc 2 the anti markownikoff addition to the carbon carbon double bond..
In chemistry, regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions [1] [2]. It can often apply to which of many possible positions a reagent will affect, such as which proton a strong base will abstract from an organic molecule, or where on a substituted benzene ring a further substituent will add.
A specific example is a halohydrin formation reaction with 2-propenylbenzene [3]:
The reaction product is a mixture of two isomers and the regioselectivity is said to be poor.
Regioselectivity in ring-closure reactions is subject to Baldwin's rules.
Moderation Team
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