KVPY Sample Paper KVPY Stream-SX Model Paper-15

  • question_answer
    Consider the following conversion:
    Which of the following sets of reagents, would successfully accomplish the conversion shown?

    A) \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}MgBr;{{H}_{3}}{{O}^{+}};PCC,C{{H}_{2}}C{{l}_{2}}\]

    B) \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}MgBr;{{H}_{3}}{{O}^{+}};{{H}_{2}}S{{O}_{4}},\text{heat};PCC,C{{H}_{2}}C{{l}_{2}}\]

    C) \[{{({{C}_{6}}{{H}_{5}})}_{3}}\overset{+}{\mathop{P}}\,-\overset{-}{\mathop{\overset{\bullet \bullet }{\mathop{C}}\,}}\,HC{{H}_{2}}C{{H}_{3}};{{B}_{2}}{{H}_{6}};{{H}_{2}}{{O}_{2}},H{{O}^{-}}\]

    D) \[{{({{C}_{6}}{{H}_{5}})}_{3}}\overset{+}{\mathop{P}}\,-\overset{-}{\mathop{\overset{\bullet \bullet }{\mathop{C}}\,}}\,HC{{H}_{2}}C{{H}_{3}};{{H}_{2}}S{{O}_{4}};{{H}_{2}}O\]

    Correct Answer: C

    Solution :

    Carbonyl compounds reacts with \[({{C}_{6}}{{H}_{5}}){{P}^{+}}\bar{\ddot{C}}HC{{H}_{2}}C{{H}_{3}}\] to form phosphoniumylide, which then gives alkenes. The formed alkenes then reacts with \[{{B}_{2}}{{H}_{6}}\] to give addition product, alkane which is in accordance to antimarkownikofFs rule.


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