Chapter 11, Problem 37IP

Interpretation Introduction

Interpretation: To propose a plausible synthesis for $1,4-\text{ dioxane}$ , starting with acetylene as the only source of carbon atoms.

Concept introduction: The retrosynthesis begins with disconnection at the ether groups, at two of the $\text{C–O}$ bonds, thereby breaking up the structure into two fragments, each with two carbon atoms. The more electronegative oxygen atom is more likely to have served as the nucleophile, so a negative charge on the oxygen atom has been drawn to give a suitable nucleophile (alkoxide ion). The carbon atom (at the disconnected bond) must have started out as an electrophile, so a leaving group (such as $\text{Cl}$ , $\text{Br}$ , $\text{I}$ or $\text{ OTs}$) at that position has been drawn:

  

Each of these starting materials can be made from acetylene.