Identify the reagent X in the following react | vedclass

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(B) The reaction involves the dehydration of $1$-cyclopentylethanol to form ethylidenecyclopentane.In the presence of strong acid catalysts like conc.

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$POCl_3$ / Pyridine

Vedclass · Answer

(B) The reaction involves the dehydration of $1$-cyclopentylethanol to form ethylidenecyclopentane.In the presence of strong acid catalysts like conc. $H_2SO_4$ or conc. $H_3PO_4$,the reaction proceeds via an $E_1$ mechanism involving a carbocation intermediate.This carbocation undergoes ring expansion (from a $5$-membered ring to a $6$-membered ring) to form a more stable product.However,the given product is ethylidenecyclopentane,which retains the $5$-membered ring.To avoid rearrangement and ring expansion,we use $POCl_3$ / Pyridine,which follows an $E_2$ mechanism and prevents carbocation formation,thus yielding the desired product without ring expansion.

Column-$I$ (Reactants)	Column-$II$ (Products)
$A$. $ROH + SOCl_2$	$i$. $RBr + NaHSO_4 + H_2O$
$B$. $ROH + PCl_5$	$ii$. $3RX + H_3PO_3$
$C$. $3ROH + PX_3$	$iii$. $RCl + SO_2 + HCl$
$D$. $ROH + NaBr + H_2SO_4$	$iv$. $RCl + POCl_3 + HCl$

Identify the reagent $X$ in the following reaction:
(Image provided)
$X$ can be $-$

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Identify the reagent $X$ in the following reaction:(Image provided)$X$ can be $-$