Carbonyls: 10 key concepts (Part 2)

April 6, 2010

5 more key concepts: Carbonyls make adjacent alkyl groups more acidic, the more electrophilic the carbonyl, the more acidic its alpha protons, carbonyls activate alkenes toward nucleophilic attack, reactivity of alpha beta unsaturated carbonyls is proportional to the stability of its enolate, enolates are nucleophiles.

Tagged as: carbonyls, enolates, nucleophilicity, pka

Read the full article →

Carbonyl Chemistry: 10 Key Concepts (Part 1)

April 4, 2010

The weaker the base, the better the leaving group. Electron withdrawing groups make the carbonyl more electrophilic. Electron donors make the carbonyl *less* electrophilic. Carboxylic acid derivatives always protonate on carbonyl first. Steric bulk slows down reactions.

Read the full article →

Nucleophile attacks Electrophile

April 1, 2010

Pretty much every reaction in organic chemistry boils down to “nucleophile attacks electrophile”.

Tagged as: electrophiles, Key Concepts, nucleophiles

Read the full article →

Summary Sheet: Additions to Carbonyls

March 31, 2010

I put together this summary sheet for the reaction of nucleophiles with carbonyls (click for larger image, see link to downloadable PDF below). It summarizes the two key concepts that are important to understand for these reactions: the effect of electronic and steric factors on nucleophilic addition.

Tagged as: carbonyls, mechanisms, org 2, Summary Sheets

Read the full article →

Some Perspective

March 16, 2010

For all of those thinking about med school: organic chemistry is not hard. . Complex? Yes. Challenging? Of course. A lot of facts and concepts to memorize and understand? Absolutely. But it’s not hard. … “Hard” is calling your patient of 20 years into your office to tell him that he has a few months to live [...]

Tagged as: rants

Read the full article →

A simple trick: The (R)-(S) Toggle

March 13, 2010

Instead of redrawing the whole molecule, just leave the hydrogen (or other 4th ranked substituent) in front and figure out whether the substituents ranked 1,2, and 3 go clockwise or counterclockwise. Then toggle (i.e. reverse direction CW to CCW or vice versa) to account for the fact that the 4th ranked substituent is in the front, and assign (R) or (S) based on that. You end up with the same answer without having to redraw anything.

Tagged as: stereochemistry

Read the full article →

Carbon is More Electronegative Than You Think

March 7, 2010

Electronegativity is one of the most useful concepts in chemistry. What makes it great is its simplicity: like GPA, it is a single number that gives an immediate mental impression of an element’s personality.

Tagged as: covalent bonding, electronegativity, General Chemistry, ionic bonding

Read the full article →

Welcome to “Orgo Hacks”

February 18, 2010

Cal Newport’s excellent blog, “Study Hacks”, inspired me to think about the problem of how to learn things in the most efficient manner possible. To many students, my field of organic chemistry (or “orgo” in the undergraduate parlance) –  has a fearsome reputation both as a weeder course and a notorious time sink. So it [...]

Read the full article →