Nucleophile, electrophile, ionic mechanism steps, Study notes of Chemistry

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Organic Chemistry 1 Resource- Week 7

Hi guys! I hope everyone is doing well! Wow, it’s already week 7!! This resource will be the second part of chapter 6 which is all about mechanisms and arrow pushing. I split up chapter 6 into 2 separate resources because this half of the chapter is crucial to your foundation for understanding the rest of O chem from here on out. So soak it

all in and make sure to get lots of practice in! Also don’t forget, Group tutoring is every Tuesday at 5:30 PM! Here’s

the link to sign up. https://www.baylor.edu/support_programs/index.php?id=

Key Words: Nucleophile, electrophile, ionic mechanism steps

Chapter 6 part 2:

Nucleophiles:

• Nucleo= nucleus (they have a positive charge), Phile= likes….. so, a nucleophile is something that likes the

positive nucleus of atoms.

o What would like something positive in nature? Something negative in nature!!

o Think of a nucleophile as something with a (-) charge or electrons to give (like a lone pair)

Ex:

Electrophiles

• Electro= electron (they have a negative charge), Phile= likes….. so, an electrophile is something that likes

negative charges

o What would like something negative in nature? Something positive in nature!!

o Think of an electrophile as something with a positive or partial positive charge.

Ex:

Mechanisms and arrow pushing: you will be doing all of these for the rest of the semester so try your hardest to understand this earlier rather than later. This chapter just describes the arrow pushing patterns that you must recognize, but the next few chapter apply them to actual reactions.

1. Nucleophilic attack

o A nucleophilic attack is the movement of the electrons from a nucleophile attacking an

electrophile.

o Remember that curved arrows show where electrons are moving to

NOTE:

double bonds

can also act

as

nucleophiles

NOTE: electronegative atoms withdraw electron density from the carbon which gives the carbon a partial positive charge making it electrophilic

Ex.

2. Loss of a leaving group

o A leaving group is something that can dissociate from the rest of the molecule

o There are good and bad leaving groups, but for now we are going to focus on good leaving

groups

o This is characterized by one arrow used to show the atom or group leaving

Ex.

3. Proton Transfers

o What is a proton? It is a hydrogen with a positive charge. So, if we are transferring only the

proton, do you think the proton is going to take its bonding electrons with it?? NO!!

o This process is characterized by 2 arrows. One arrow shows a base grabbing a proton and the

second arrow shows the proton giving its electrons back to whatever it is connected to. Ex.

Practice Questions!!! Identify the mechanisms (answers on last page)

Answers to practice:

1. Hydride shift
2. Loss of a leaving group
3. Nucleophilic attack
4. Proton transfer