Alcohols: Multi-Step Synthesis - Set #II
Suggest a synthetic scheme for the conversion shown on the left using the starting materials shown below. Work each problem backwards, and draw the structures of the intermediates required for the conversion, and the reaction conditions necessary for each step.Click the mouse on the buttons to view the synthetic logic for each step, the structures of the intermediates and the solution to the problem;
click here to view the potential starting materials.
Click the mouse on the molecule to reset this frame.
Working backwards, this molecule contains a cyclohexene ring which and a simple aldehyde substituent. None of the cyclic starting materials appears to offer a simple route to this molecule. An appropriate carbon skeleton could be built, however, from allyl alcohol (2-propen-1-ol) using a 4+2 cycloaddition reaction. The resulting alcohol can be partially oxidized to give the aldehyde.
Since none of the cyclic starting materials offers a simple route to this molecule, the carbon skeleton can be constructed using a 4+2 cycloaddition reaction between allyl alcohol (2-propen-1-ol) and 1,3-butadiene. In this step, the alcohol is oxidized to the aldehyde using PCC in CH2Cl2. Next, show the structure of the reactants necessary for the cycloaddition reaction.
Allyl alcohol (2-propen-1-ol) is first reacted with 1,3-butadiene to give (3-cyclohexenyl)methanol. The alcohol is then converted to the aldehyde by partial oxidation with PCC in CH2Cl2.