Question

please answer the question

Undergraduate student Paula Lanthanum in the Burrows lab works on the synthesis of europium(III) coordination complexes. Much of her time is spent assembling different building blocks to construct the ligand structure prior to the complexation reaction. One of these building blocks, product, is shown in Figure 1. Paula obtains this molecule is the product of a Sonogashira reaction, where she uses reagents Pd(PPha), Cul, NEts, THF as solvent, as well as her reactants 1 and 2. 0 The rudimentary catalytic cycle is shown below. Figure 1. Product Pd (PPh:) 1.) Draw the structure of the reactants 1 and 2 that Paula needs in order to synthesize her building block using the Sonogashira coupling (multiple answers are possible). 2.) Complete the catalytic cycle by filling in the missing intermediates 11, 12 and 13 with correct structures. Name the individual reaction steps. 3.) Count the total number of electrons of each complex and determine the formal charge of each Pd center. 4.) The Sonogashira coupling is highly moisture sensitive and needs to be carried out in conditions that exclude water. Indicate which reaction steps may be impacted if H2O finds its way into the reaction vessel!

Answer 1

Reactant - 1 = Reactant- 2 = 1 1₂(THE), Reductive Elimination oxidative addition (13) pphy 04 Trans cu- Metaliation NE & Trans/cis Isomerization cul Nitza Phyt – Pt PPhz 12

Total no. of elections in It (se from ligands & 8 e from Pd (17) center) = 16e 10 valance e - 18 nonbonding & + 4 bonds) = -2 (8 e from ligands & 8e from Pd (II) center) formal charge on Pd-center Total no. of elections in 12 =16e Formal charge on pd - center - 10- (8+4) = -2 Total no. of elections in 13 (8 e from ligands & 8 e from Pd (17) center) = 16e formal charge on Pd - center 10 (8+4)= -2 Total no eiections in pd (PPhy),(The), 7(8e- from ligands t toe hom Pedley C = 18 e formal charge on Pd center 10- (10+4) = -4

The formation of copper-acety life and 1 The transmetallation step are highly affected it water is present during the Sonogashira reaction.

1. catalytic cycle is drawn, including the reactant-1 and reactant-2.

2. Names of all the steps are mentioned.

3. Total number of electrons and formal charges on Pd-center is calculated.

4. Acetylide formation and trans-metallation steps will be affected in presence of water.