Bombykol is the mating pheromone of the female silkworm moth Using the result in Problem 18 89, propose a synthesis of bombykol, using both HC C(CH 2 ) 9 OH (10 undecyne 1 ol) and 1 pentyne as starting materials Problem 18 89 When vinylic boronic acids are treated with Br 2 and then with NaOH, viny...

First recognize that the bombykol carbon skeleton is comprised of only the 10undecyne1ol and 1pentyn ...

Bombykol is the mating pheromone of the female silkworm moth. Using the result in Problem 18.89, propose

Question:

Bombykol is the mating pheromone of the female silkworm moth. H C=C H CH3CHCH C=C H bombykol H (CH),OH

Using the result in Problem 18.89, propose a synthesis of bombykol, using both H—C ≡ C(CH₂)₉OH (10-undecyne-1-ol) and 1-pentyne as starting materials.

Problem 18.89

When vinylic boronic acids are treated with Br₂ and then with NaOH, vinylic bromides are formed with inversion of configuration, as shown in Fig. P18.89a. But when vinylic boronic acids are treated with I₂ in the presence of NaOH, vinylic iodides are formed with retention of configuration, as shown in Fig. P18.89b. Suggest mechanisms that account for these results. (a) 20 R H (b) R H C=C C=C Figure P18.89 H B(OH)2 H B(OH) 1) Br in CHCl 2) NaOH 12, NaOH R H R H C=C =C H Br