Chapter 24, Problem 45P

Although diazomethane $\left({\text{CH}}_{\text{2}}{\text{N}}_{\text{2}}\right)$ is often not a useful reagent for preparing cyclopropanes, other diazo compounds give good yields of more complex cyclopropanes. Draw a stepwise mechanism for the conversion of diazo compound A to B, an intermediate in the synthesis of sirenin, the sperm attractant produced by the f emale gametes of the water mold Allomyces.