91Ó°ÊÓ

Outline a synthesis of each Wittig reagent from \(\mathrm{Ph}_{3} \mathrm{P}\) and an alkyl halide. a. \(\mathrm{Ph}_{3} \mathrm{P}=\mathrm{CHCH}_{3}\) b. \(\mathrm{Ph}_{3} \mathrm{P}=\mathrm{C}\left(\mathrm{CH}_{3}\right)_{2}\) c. \(\mathrm{Ph}_{3} \mathrm{P}=\mathrm{CHC}_{6} \mathrm{H}_{5}\)

Draw the products (including stereoisomers) formed when benzaldehyde \(\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}\right)\) is treated with each Wittig reagent: (a) \(\mathrm{Ph}_{3} \mathrm{P}=\mathrm{CHCH}_{2} \mathrm{CH}_{3} ;\) (b) \(\mathrm{Ph}_{3} \mathrm{P}=\mathrm{CHC}_{6} \mathrm{H}_{5} ;\) (c) \(\mathrm{Ph}_{3} \mathrm{P}=\mathrm{CHCOOCH}_{3}\).

Draw the product formed when phenylacetaldehyde \(\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{CHO}\right)\) is treated with each reagent. Phenylacetaldehyde is partly responsible for the fragrance of the flowers of the plumeria tree, which is native to the tropical and subtropical Americas. a. \(\mathrm{NaBH}_{4}, \mathrm{CH}_{3} \mathrm{OH}\) e. \(\mathrm{Ph}_{3} \mathrm{P}=\mathrm{CHCH}_{3}\) b. \([1] \mathrm{LiAlH}_{4} ;[2] \mathrm{H}_{2} \mathrm{O}\) f. \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CH} \mathrm{NH}_{2}\), mild acid c. \([1] \mathrm{CH}_{3} \mathrm{MgBr} ;[2] \mathrm{H}_{2} \mathrm{O}\) g. \(\left(\mathrm{CH}_{3} \mathrm{CH}_{2}\right)_{2} \mathrm{NH}\), mild acid d. \(\mathrm{NaCN}, \mathrm{HCl}\) h. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}\) (excess), \(\mathrm{H}^{+}\) i. \(\mathrm{NH}\), mild acid j. \(\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{OH}, \mathrm{H}^{+}\)

Explain why a gem-diol is the major species present at equilibrium when cyclopropanone is dissolved in \(\mathrm{H}_{2} \mathrm{O}\).