4. Sketch the MO diagram for C4H2, (CAH-CB-C㎝CoH). Diacetylene. a. Determine and draw-framework: b. How many pairs of electrons are in the σ-framework? How many pairs of electrons are in the π-framework? d. Draw energy diagram for Tt framework: e. How many pairs of electrons are shared between the middle two carbons in C4H2, f. How many pairs of electrons are shared between the first two carbons in CaH2 c.

(10, 6) Draw structural formulas for all of the enol forms of the carbonyl compounds below. You do not have to consider stereochemistry. Consider stereoisomeric enols as a single enol form. In the case of dicarbonyl compounds, do not include stuctures in which both carbonyl groups are present as enols.

Consider the following curved arrow transformations. For each correct transformation draw the result of the movement indicated by the curved arrow. For each incorrect transformation state why the curved arrow is incorrect.

4. (10 points) Complete the reaction scheme below. Show all reagents and intermediates. No reaction is a possible answer. LDA lodomethane CH3 H H

HCHO2 + H2O E--→CHO21 + H3O* when the [CHO,1] increases then which of the following will occur? a) [H2O] inc. b) [HCHO2] dec. c) [H3O*] inc. d) they all increase T

1. Propose a mechanism for the following reaction. (10 points) Br₂ OH Br 29. on HBr

1. +. F5 F7 F8 F10 F11 F12 Insert & ) ( 7. 6 8. Draw the detailed mechanisms for the following transformations. OCH3 H3C 0CH 3 (1.5 equiv) then reflux, 5h 56% CH3 CICH,CH,CI, hv 19.5h N2 N. HO