Alkynes

Alkyne Reaction Patterns – The Carbocation Pathway

May 24, 2013

In the previous three posts on alkynes we’ve introduced some new reactions that are specific to alkynes (versus alkenes): deprotonation (and subsequent substitution), partial reduction to alkenes, and the formation of aldehydes and ketones through net “hydration”. With all the focus on the ways in which alkyne chemistry can differ from alkene chemistry, it’s helpful [...]

Tagged as: addition, carbocation, geminal dihalide, hbr, hcl, hi, markovnikov, vinyl hallide

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Hydroboration and Oxymercuration of Alkynes

May 14, 2013

Alkyne chemistry bears many resemblances to alkene chemistry, but in these first few posts on the subject, the purpose is to illustrate how one seemingly minor change – an extra π bond – can lead to significant differences in chemical behavior. Previously, we saw that the sp hybridization of alkynes leads to increased acidity, and the [...]

Tagged as: alkenes, alkynes, enol, hydroboration, markovnikov, mercuration, oxymercuration, tautomerism

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Partial Reduction of Alkynes

May 8, 2013

Alkynes bear many similarities to alkenes, but as we have already seen, their chemistry can differ in subtle and interesting ways. Today’s post is another case in point. The reduction of alkenes by hydrogen in the presence of a metal catalyst (“catalytic hydrogenation”) is a time-honoured reaction recognized by Sabatier’s receipt of the Nobel Prize for [...]

Tagged as: alkyne reduction, cis alkene, lindlar, na/nh3, sodium, trans alkene

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The 2 Most Important Reactions of Alkynes

May 1, 2013

With the series of posts on alkenes in the can, let’s move on and talk about a closely related functional group that shares many reactions in common with alkenes: acetylenes, or as they are more commonly referred to, “alkynes”. Alkynes, as we shall see, do share many reactions in common with alkenes. However there are [...]

Tagged as: acidity, alkynes, SN2, sp, substitution, synthesis

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Reaction Friday – Reduction of Alkynes to Alkenes with Na/NH3

Reaction Friday – Reduction of Alkynes to Alkenes with Na/NH3

April 6, 2012

My apologies for the interruption. I seem to have wrested control of my blog back from the cats for now, but I’m not sure how long this will last. Clever little bugger. One thing I can say though – the cat picked a lot of questions to answer that I’d been ignoring because they seemed [...]

Tagged as: alkenes, alkynes, Na, NH3, Reaction Friday, reduction, sodium, stereoselective, trans

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Reagent Friday: Sodium (Na)

Reagent Friday: Sodium (Na)

October 7, 2011

In a blatant plug for the Reagent Guide and the Reagents App for iPhone, each Friday  I profile a different reagent that is commonly encountered in Org 1/ Org 2.  Today’s topic, sodium metal is a pretty notorious reagent. You might know it from Youtube as “That solid that you drop in water and blows things up, a property [...]

Tagged as: alkene, alkynes, reagent app, Reagent guide, reagents, reducing agents, stereoselective, trans

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Reagent Friday: Lindlar’s Catalyst

Reagent Friday: Lindlar’s Catalyst

August 19, 2011

In a blatant plug for the Reagent Guide, each Friday  I profile a different reagent that is commonly encountered in Org 1/ Org 2. Version 1.2 just got released, with a host of corrections and a new page index.  One thing that’s useful to keep in mind as you learn about reagents is that there are [...]

Tagged as: alkynes, catalyst, cis, hydrogenation, lindlar, partial reduction, reagent friday, Reagent guide, reducing agent, stereoselective, syn

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Summary Sheet #8: The Oxidation Ladder

August 15, 2011

Following up on this post, here’s an attempt at trying to put many of the reactions in organic chemistry in perspective, from the standpoint of oxidation state. Note that there’s a lot of gaps – very little on amines, for instance, and no treatment of epoxides or diols – but I hope that people will [...]

Tagged as: oxidation, oxidizing agents, reducing agents, reduction, Summary Sheets

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Oxidation Ladders

August 8, 2011

Once you get a handle on oxidations and reductions, you might start to notice that with some molecules these reactions can proceed in sequences. For example, if you start with an alkane with a CH3 group, the alkane can be oxidized to a primary alcohol. The alcohol can be oxidized to an aldehyde The aldehyde [...]

Tagged as: alcohols, aldehydes, alkenes, carboxylic acids, oxidation, reduction

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The Organic Chemistry Reagent Guide is here!

May 26, 2011

It’s taken a long time – late April through early May was hectic – but today I’m thrilled to finally announce the launch of the “Organic Chemistry Reagent Guide“, a guide designed especially for undergraduate students taking Org1/Org 2. It’s has pretty much all the reagents you need to know about, from Ag2O to Zn(Hg). [...]

Tagged as: acids, bases, oxidants, reagent friday, Reagent guide, reagents, study tips, Summary Sheets

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