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The SIN reaction requires three qualities: a strong nucleoli, a good, unhindered leaving group, and a polar, apricot solvent. For our reaction, we have all three bases covered. The nucleoli is an alkaloid, a depredation alcohol. Technically, because our alcohol is a phenol, the conjugate base is called a phenotype. Phenol itself has a peak of about 10, but our alcohol has more resonance opportunities, so the peak is down around 8. This is sufficiently acidic for use of weak base like CHECK for depreciation (Scheme 1). The acidic of the alder also helps in purifying the crude product.
Our conditions call for excess alder, which we will wash away with base in the work-up. Aside from a good nucleoli, we also have a good, unhindered leaving group in the bromine atom in cinnamon bromide. Note that not only is this reagent a primary halide, but it also has no _-hydrogen (so no E is possible). Finally, our reaction solvent is DMS (N,N-dehumidification), a classic solvent for SIN reactions. With all the conditions in favor of this reaction, it should be no surprise that this reaction works very well Despite the ease of our reaction, a few comments are in order.
Our alkyl halide, cinnamon bromide, is extremely reactive. As an electroplate, it is activated by something called the phenyl effect (Reeve J. Am. Chem.. Soc. 1954, 76, 228(:)-2281). The phenyl effect applies to halides that are adjacent to a _-bond, such as a simple double bond, an aromatic ring, or a carbonyl. The neighboring _-bond stabilizes both SIN substation and SIN unionization (Figure 1). With this type of halide, the choice of solvent is extremely important. Despite being portico, alcohols can often be used as a solvent in many SIN reactions.
Unfortunately, ethanol reacts quickly with cinnamon bromide under basic conditions to give a substation product either by an SIN (more likely) or SIN pathway (Scheme 2). DMS (timely sulfide) is also a traditional SIN solvent. However, DMS is sufficiently necrophilia at oxygen to attack cinnamon bromide. Ultimately, the halide is oxidized to an alder in a process called the Cornball reaction