Question

Describe where the "Reference Carbon" (the one that determines if the structure is D or L) is located in a carbohydrate with more than one asymmetric carbon

Answer 1

Farthest from the carbonyl carbon.

Step-by-step explanation:

Reference carbon that determined the absolute D and L configuration is located farthest from the carbonyl carbon.

In other words, reference carbon is that assymentric carbon which is located farthest from the carbolyl carbon and has configuration similar to D- or L-glyceraldehyde isomers.

D and L configuration is decided by the direction of -OH group attached to the reference carbon.

In L-isomer, -OH group is attached to the left side of the reference carbon and in D-isomer, -OH group is attached to the right side of the reference carbon.