Account for the regioselectivity and stereoselectivity observed when this compound is treated with Br₂ in H₂O by drawing the final product in the reaction. • Use wedge and hash bonds ONLY when needed to show reaction stereochemistry. • If the reaction produces a racemic mixture, just draw one stereoisomer.

[Review Topics] [References] An alkene having the molecular formula C6H10 is treated sequentially with ozone (03) and zinc/acetic acid to give the product/s shown. CH3CCH,CH,CH2CH Draw a structural formula for the alkene. • You do not have to consider stereochemistry. • You do not have to explicitly draw H atoms. • In cases where there is more than one answer, just draw one. P. aste Ado ChemDoodle Previous Next

Explain why stereochemistry is observed in this compound.

True or False: Acetylene is a naturally occurring conjugated diene   True or False: The Diels-Alder reaction has the stereochemistry of the dienophile is retained in the product.     True or False: When looking at kinetic vs. thermodynamic products the kinetic product predominates at low temperature.   True or False: the mechanism of the Diels-Alder reaction is three π bonds break; one σ bond and two π bonds form.

When heated, allyl aryl ethers and allyl vinyl ethers undergo a reaction called a Claisen rearrangement, a concerted reorganization of bonding electrons similar to the Diels-Alder reaction. The reaction proceeds through a six-membered, cyclic transition state. Draw the structure of the expected product when this compound undergoes a Claisen rearrangement. You do not have to consider stereochemistry. For the purposes of this problem, assume that double bonds in an aromatic ring are localized at the positions indicated in the figure. Include isomerization to a phenol IF appropriate.

The following compound reacts with NaOMe in an SN2 reaction. Draw the transition state and the final product of the reaction and use the transition state geometry to explain the stereochemical outcome of the reaction. What is the side-reaction that might occur and what would be the major product of that reaction? Br NaOMe ČH3

1. In the lecture on the reactions of alkenes, we studied the reaction of alkenes with N- Bromosuccinimide (NBS), which went through a mechanism involving an allylic radical (the radical is a carbon attached to a carbon involved in a л bond). What if there were a conjugated system? Draw, using curved arrows, the three resonance forms of cyclohexadienyl radical:

Draw the four major products that form, including stereoisomers, in the bromination of cyclopentene with Br2 and light. Make sure you draw all four bonds at all stereocenters. Br₂ hy

Optical active compound 1-chloro-3-methylcyclopentane was reacting withpotassium t-butoxide in t-butanol. Two alkene products were obtained. Themain product was optically active, and the secondary product was notoptically active. What are the two products?

Draw An energy diagram for the SN1 reaction: (CH3)3CBr+ CH3CO2−→(CH3)3COCOCH3 + Br−