Question

Sterist CH; HC CHH; CCH; - CC CH trans vinylic anion more stable anion able cis vinylic a less stab electron repulsion cis radical anion less stable Hical anion is more stable than the cis radical anion, because the nonbonded electrons are farther apart i The trans vinylic anion is more stable than the cis vinylic anion, because the relatively bulky alkyl group in the trans isomer (Section 5.9). PROBLEM 19 Describe the alkyne you should start with and the reagents you should use if you want to synthesize a. pentane. b. cis-2-butene. c. trans-2-pentene. d. 1-hexene. PROBLEM 20 What are products of the following reactions? - + H₂ Pd/C 1. R BH/THE 2. HO, H2O2, H20 + H Lindlar catalyst e. -= 1. R2BH/THE 2. HO, H2O2, H20 Na NH (liq) -78 C + HO H2SO4 1.10A HYDROGEN BONDED TO AN sp CARBON IS “ACIDIC" We saw that an sp carbon is more electronegative than an sp carbon, which is more electronegative than an sp carbon (Section 2.6). relative electronegativities of carbon atoms most electronegative sp sp > sp l east electronegative Because the most acidic compound is the one with its hydrogen attached to the most electronegative atom (when the atoms are the same size), ethyne is a stronger acid than etheme and oth acid than ethane.
for question 19 can you explain why you picked the reagents you did?

Answer 1

Alkylation of alkyne is an example for sn2 reaction

And Lindlars catalyst reduces the alkyne into cis Alkene.

Li/liq.NH3 reduces the alkyne into trans alkene.

With excess H2/Pd , reduce the alkyne into alkane.

994/Subject: 2 H NaNH 19 10 ASH - CH₃ I Nanth 1 Ft Nawth Hz Hz CHI Lindlard Nanha HI Lig - NH) Nanth Lindlagt