The nomenclature of naturally occurring D-Fructose is officially written as D-(-)-Fructose. What cri — Isomerism and Stereochemistry Chemistry Question
Question
The nomenclature of naturally occurring D-Fructose is officially written as D-(-)-Fructose. What critical stereochemical principle does the coexistence of 'D' and '(-)' unequivocally prove?
Answer: B
💡 Solution & Explanation
A massive trap in stereochemistry is assuming 'D' means dextrorotatory (+). Capital 'D' and 'L' strictly define the static, relative 2D structural configuration drawn on paper. Lowercase 'd' (+) and 'l' (-) denote the physical, experimental direction of optical rotation in a polarimeter. They have zero theoretical correlation, meaning a 'D' configured molecule can absolutely be levorotatory (-).
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