1559T_ch13_247-25811/03/0520:12Pa9e258 ⊕ EQA 258.Chapter 13 ALKYNES:THE CARBON-CARBON TRIPLE BOND The model study suggests that addition to a carbonyl groun is superior to simple displacement reactions fo formation of the required medium-sized ring.Soit would be reasonable to try something like the following OH OCH 50.(b)5-Chloro-1-pentyne would be equally correct 51.(d 52.a 53.(a 54.(d ⊕ The model study suggests that addition to a carbonyl group is superior to simple displacement reactions for formation of the required medium-sized ring. So it would be reasonable to try something like the following: 50. (b) 5-Chloro-1-pentyne would be equally correct. 51. (d) 52. (a) 53. (a) 54. (c) OCH3 OCH3 OCH3 RN OH O H CH3 OCH3 OCH3 OCH3 RN OH O CH3 H 1. PCC, CH2Cl2 (oxidizes OH group) 2. LDA (deprotonates which attacks C C H, O) 258 • Chapter 13 ALKYNES: THE CARBON–CARBON TRIPLE BOND 1559T_ch13_247-258 11/03/05 20:12 Page 258