Simplest way to find R/S nomenclature in cross formula

Cool goIITian

Posted on
8 May 2011 17:56:57 IST

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8 May 2011 17:56:57 IST

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Simplest way to find R/S nomenclature in cross formula

Engineering Entrance , JEE Main , JEE Advanced , Chemistry , Inorganic Chemistry

The trick is that if a lower priority group in horizontal line then the configuration so found in cross formula get reversed and if lower priority group in vertical then the configuration is same as we find in the cross formula .

Let's take an example of tartaric acid here in 2C , H is in vertical and here 2R is found and then reversed so 2S and in 3C case 3R is found then reversed so 3S

So the final R/S configuration of the compound is found to be 2S , 3S

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