Dichloro-2-pentyne

Assume that you need to prepare 4 methyl 2 pentyne and discover that the only alkynes on hand are acetylene and propyne You also have available methyl iodide isopropyl bromide and 1 1 dichloro 3 methylbutane Which of these compounds would you choose in order to perform your synthesis and how would you carry it out" ... 

In acetic acid, both 1-pentyne and 1-hexyne give the syn addition product. With 2-butyne and 3-hexyne, the major products are p-chlorovinyl acetates of //-configuration.154 Some of the dichloro compounds are also formed, with more of the E- than the Z-isomer being observed. 

Problem 12.46. Which of the following exist as a pair of cis and Irons isomers Show structures of the cis and trans isomers, (a) 4-Methyl-2-pentene, ib) 2,4-dimethyl-2-pentene, (c) 4-methyl-2-pentyne, (dichloro-cyclopropane, (e) 1,2-dichlorocyclopropane. 

Key precursors in the preparation of zoxamide are 3,5-dichloro-4-methylbenzoyl chloride (16) and 3-amino-3-methyl-l-pentyne (17). Compound 16 is prepared... 

Indicate whether each of the following molecules is capable of geometrical (cis-trans) isomerism. For those that are, draw the structures (a) 1,1-dichloro- 1-butene, (b) 2,4-dichloro-2-butene, (c) 1,4-dichlorobenzene, (d) 4,5-dimethyl-2-pentyne. 

---