A crotyl group is an organic functional group with the formula RCH2CH=CHCH3. Systematically, it is called a but-2-en-1-yl group and exhibits geometric isomerism, being either cis (Z) or trans (E). There are many simple compounds in which the crotyl group forms base carbon chain: crotyl alcohol, crotonaldehyde, crotonic acid, and crotyl acrylate are examples.
Crotylate (crotyl anions) can be synthesised from 2-butene (either isomer): this reaction must be performed in the presence of organometallic reagents, as a base, usually alkyl lithium, or any alkylates of s-block metals, in a solvent, typically THF, and at low temperatures, generally below -20 °C. The negative charge is delocalised over three of the carbon atoms of the crotylate group and there is resonance between the two possible delocalised forms (one for each terminal carbon).
Crotylation readily occurs with alkoxy boronates to form crotylboronates.
Crotylboronates are useful reagents in the formation of crotyl alcohols. They react with the acidic protons of aldehydes to form alcohols. The mechanism involves a six-membered ring involving the carbonyl oxygen and boron in a chair-like structure. Such reactions are highly diastereoselective.
I'm out of faith, I'm in retrograde
A dizzy pattern in a cheap parade
And I'm losing touch but I'm, I'm not ashamed
Of what I say or how nice I play
I'm a Trojan horse made of paper mache
What has been ever comes 'round again
And I'm under a rain, I'm shutting down
I'm unimpressed but I've done my best
An undecided heart makes such a mess
I'm out of place, I'm a different state
A little scattered by a bitter fate
And I'm losing touch but I'm, I'm not afraid
I'll be okay just in a different way
I have no remorse, I have no more shame
Oh, nothing ever ends before it begins
'Cause I'm under a rain, I'm shutting down
I'm unimpressed but I've done my best
An undecided heart makes such a mess
Well, I'll be going 'round and 'round
This cycle won't slow down
I'm looking for the center of this life I've found
What has been ever comes 'round again?
'Cause I'm under a rain, I'm shutting down
I'm unimpressed but I've done my best
An undecided heart makes such a mess
And I'm under a rain, I'm shutting down
I'm unimpressed, I've done my best