Anti Addition vs Syn Addition - Alkene Reactions

TL;DR

Different reagents result in either anti-addition or syn-addition when reacting with one methyl cyclohexene.

Transcript

number 30 which of the following reagents will proceed with anti-addition upon reacting with one methyl cyclohexene so let's draw the reactant so this is one methyl cyclohexane and let's begin by reacting it with hydrogen gas using a platinum catalyst now just to color code this I'm going to make this red now keep in mind there is a hydrogen atom h... Read More

Key Insights

• 🕍 Different reagents can result in either anti-addition or syn-addition when reacting with one methyl cyclohexene.
• 😘 Hydrogen gas with a platinum catalyst leads to sin-addition.
• 🕍 Potassium permanganate under basic conditions results in dihydroxylation with syn-addition.
• 😘 Hydroboration with BH3 THF followed by oxidation leads to sin-addition.
• 🇦🇬 Reacting with Br2 and methanol proceeds with anti-addition.
• ❓ The addition pattern can be regioselective and stereoselective.
• ❓ Alkene reactions can produce multiple stereoisomers, but some reactions produce specific stereoisomers.

Summary & Key Takeaways

• Hydrogen gas with a platinum catalyst results in sin-addition, adding two hydrogens on the same side across the double bond.

• Potassium permanganate under basic conditions leads to dihydroxylation with syn-addition, producing a diol.

• Hydroboration with BH3 THF followed by oxidation with hydrogen peroxide and hydroxide results in sin-addition, adding an OH group to the less substituted carbon and a hydrogen to the more substituted carbon.

• Br2 with methanol proceeds with anti-addition, adding a bromine atom to the less substituted carbon and an OCH2 group to the more substituted carbon.