Predict the product(s) for each of the following elimination reactions. In each case show the mechanism. What do the mechanisms have in common? Why? OH H2SO4 (a) (b) Cl CH3 -OH CH3 H (c) CS Scanned with CamScanner CH3CO2Na CH3CO2H H2SO4 3

Suggest a mechanism for the following reactions. Each will require multiple types of concerted pericyclic reactions (cycloaddition, electrocyclic, and sigmatropic. Classify each reaction type. Me3Si Me3Si Me Si Me Sil g H

When cis-2-decalone is dissolved in ether containing a trace of HCl, an equilibrium is established with trans-2-decalone. The latter ketone predominates in the equilibrium mixture. Propose a mechanism for this isomerization and account for the fact that the trans isomer predominates at equilibrium.

It is not uncommon for organic chemists to prepare acetals by an exchange-type process known as transacetalization. Predict the product(s) and show the mechanism for the transacetalization reactions below.

A step in a synthesis of PGE1 (prostaglandin E1, alprostadil) is the reaction of a trisubstituted cyclohexene with bromine to form a bromolactone. Propose a mechanism for formation of this bromolactone and account for the observed stereochemistry of each substituent on the cyclohexane ring. Alprostadil is used as a temporary therapy for infants born with congenital heart defects that restrict pulmonary blood flow. It brings about dilation of the ductus arteriosus, which in turn increases blood flow in the lungs and blood oxygenation.

Meerwein's reagent, triethyloxonium tetrafluoroborate, is a powerful ethylating agent that converts alcohols into ethyl ethers at neutral pH. Show the reaction of Meerwein’s reagent with cyclohexanol, and account for the fact that trialkyloxonium salts are much more reactive alkylating agents than alkyl iodides. (CH3CH2)3O+ BF4- Meerwein's reagent

Predict the product(s) and provide the mechanism for each reaction below.

Aldehydes and ketones react with thiols to yield thioacetals just as they react with alcohols to yield acetals. Predict the product of the following reaction, and propose a mechanism:

Provide the structure of the product(s) with stereochemisty if appropriate. If multiple products indicate major product or if products are formed in equal amounts. If there is no reaction expected explain why. (a) OH HIO4 (the protecting group is remained) CHO H HOH2C OH (b) CHO -ОН NaCN # HO -H H -OH CH₂OH (c) CHO HO- -H HO -H NH₂OH 張一 H -OH H -OH CH₂OH i) Ba(OH)2 ii) MeOH, H₂SO4 NaOAc Ac₂0 NaOMe MeOH

Jut L Br HNO3/H₂SO4 NaOEt M N K (i) Give the structure of M and a mechanism for its formation. L and of bromoquinoline Explain the reactivity regioselectivity of the reaction. (ii) Give the structure of N and a mechanism for its formation. and bromoquinoline L Explain the reactivity of regioselectivity of the reaction.