Syn addition reactions

Syn stereochemistry (Section 7.5) The opposite of anti. A syn addition reaction is one in which the two ends of the double bond react from the same side. A syn elimination is one in which the two groups leave from the same side of the molecule. 

The reaction of alkenes with peroxycarboxylic acids (or peracids) leads to the formation of epoxides in a concerted addition reaction. The peroxycarboxylic acid donates an oxygen atom to the double bond in a syn- addition reaction. 

In a catalytic hydrogenation, the alkene sits on the surface of the metal catalyst and both hydrogen atoms add to the same side of the double bond (Section 4.11). Therefore, the addition of H2 to an alkene is a syn addition reaction. 

The Diels-Alder reaction is a syn addition reaction with respect to both the diene and the dienophile One face of the diene adds to one face of the dienophile. Therefore,... 

For reactions (a) and (b) the 1,3-dipolar compound will be found in the first step, whereas in reaction (c) it is given. 1,3-cycloadditions are syn addition reactions they add cis to the multiple bond due to stereochemical restrictions. 

Catalytic Hydrogenation and Other Palladium-Catalyzed Reactions via Hydropalladation, Metallopalladation, and Other Related Syn Addition Reactions without Carbon-Carbon Bond Formation or Cleavage... 

VII.6 Palladium-Catalyzed Syn-Addition Reactions of X—Pd Bonds (X = Group 15,16, and 17 Elements)... 

The addition of H2 or a peroxyacid to an alkene is a syn addition reaction hydroboration-oxidation is overall a S5U1 addition of water. 

The Diels-Alder reaction is a syn addition reaction. One face of the diene adds to one face of the dienophile. Therefore, if the substituents in the dienophile are cis, then they will be cis in the product if the substituents in the dienophile are trans, then they will be trans in the product. Because each of the following reactions forms a product with two new asymmetric centers, a pair of enantiomers is formed (Section 6.15). The stereochemistry of the reaction will be discussed in greater detail in Section 28.4. 

Because carbon is more electronegative than palladium, R is a nucleophile. It adds to the sp carbon of the alkene and the electrons of the tt bond add to palladium. This is a syn addition reaction. 

---