1 The Diels-Alder reaction is a conjugate addition reaction of a conjugated diene to an alkene (the dienophile) to produce a cyclohexene. 2  The simplest example is the reaction of 1,3-butadiene with ethene to form cyclohexene:3  The analogous reaction of 1,3-butadiene with ethyne to form 1,4-cyclohexadiene is also known: Due to the high degree of regio-and stereoselectivity (due to the concerted mechanism), the Diels-Alder reaction is a very powerful reaction and is widely used in synthetic organic chemistry.
Best Answer: Buyers have up 7 days to pay for an item before you as a seller can open an unpaid item case with ebay. They have a whole process they ask that sellers follow: Buyers automatically enter into a legally binding contract to purchase the item from the seller if they win an online auction or use the Buy It Now feature.
Unfortunately, you need to wait approximately 14 days from the non-paying buyer's buy date before you relist the item. This is how it works: In eBay terms, the buyer has 7 days to pay for the item before you can open an unpaid item claim. After you open an unpaid item claim, the buyer has an additional 7 days to pay for the item. After that period of time, you can file for a refund of your listing fees and then relist the item.