Organic chemistry.(Brief Article)

Making bonds without by-products is part of the ecofriendly thinking of modern synthetic organic chemistry. Of course, unless we do our chemistry in the solid state or gas phase, or as a melt, there will always be waste solvents to concern us, but reactions without reagents do offer a legitimate environmental benefit. Cycloaddition reactions are by far the most common example, and are attractive from a strategic standpoint as well because several bonds are made in one step. Our first two examples exploit phenolic and aminoarene functionality to prepare for the cycloaddition process (and use conventional reagents for this purpose). The hydroxybenzaldehyde (1) is condensed with alcohol derivatives such as (2) to …