User:Benjah-bmm27/degree/3/GCLJ2: Difference between revisions
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* Catalysed by <sup>0</sup>PdL<sub>2</sub> |
* Catalysed by <sup>0</sup>PdL<sub>2</sub> |
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* [R′H<sub>2</sub>N<sup>+</sup>PdL<sub>2</sub>R][X<sup>−</sup>] deprotonated |
* [R′H<sub>2</sub>N<sup>+</sup>PdL<sub>2</sub>R][X<sup>−</sup>] deprotonated |
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==sp³ hybridised carbon in the oxidative addition process== |
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==Heck reaction== |
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* [[Heck reaction]] |
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** Named after [[Richard Heck]] who developed the reaction in the 1970s |
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==Other interactions of alkenes with Pd(II)== |
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* [[Allylic rearrangement]]s |
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==Cyclopropanation using electrophilic carbene complexes== |
==Cyclopropanation using electrophilic carbene complexes== |
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* [[Cyclopropanation]] using electrophilic [[carbene]] complexes |
* [[Cyclopropanation]] using electrophilic [[carbene]] complexes |
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** [[Transition metal carbene complex|Carbene complexes]] are often called [[carbenoid]]s |
** [[Transition metal carbene complex|Carbene complexes]] are often called [[carbenoid]]s |
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** [[Cyclopropanes]] are found in nature as [[pyrethrin]]s, and are produced synthetically as [[pyrethroid]] insecticides |
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** Use [[ethyl diazoacetate]] as a source of :CEt<sub>2</sub> (or more generally use R<sub>2</sub>CN<sub>2</sub> as a source of :CR<sub>2</sub>) |
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** Use an [[alkene]] as a source of R<sub>2</sub>C<sup>•</sup>—<sup>•</sup>CR<sub>2</sub> |
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** R<sub>2</sub>C: + R<sub>2</sub>C<sup>•</sup>—<sup>•</sup>CR<sub>2</sub> → cyclo-(R<sub>2</sub>C)<sub>3</sub>, i.e. a cyclopropane |
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** Cu or Rh catalyst |
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===Cilastatin synthesis=== |
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==Ring-closing metathesis== |
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* [[Ring-closing metathesis]] |
* [[Ring-closing metathesis]] |
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** catalysed by [[Grubbs' catalyst|Grubbs' first generation catalyst]], Cl<sub>2</sub>(Cy<sub>3</sub>P)Ru=CHPh |
** catalysed by [[Grubbs' catalyst|Grubbs' first generation catalyst]], Cl<sub>2</sub>(Cy<sub>3</sub>P)Ru=CHPh |
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Revision as of 13:35, 23 April 2010
Synthetic uses of transition metals, GCLJ
Textbooks
- Clayden, Chapter 48 (Organometallic chemistry), pp. 1311–1343
Introduction
- Organopalladium chemistry
- R-Pd-X species are not [R−][+PdX]
- no carbanionic character
- not basic or nucleophilic
- react with nucleophiles (pi donors, R′-M)
- Pd(II) slightly electrophilic
- R-Pd-X species are not [R−][+PdX]
- Transmetallation
- Tris(dibenzylideneacetone)dipalladium(0), Pd2(dba)3
Pd-catalyzed coupling reactions
Stille
Suzuki
- Suzuki coupling
- use catecholborane to form vinylborane precursor
- use Pd(PPh3)2Cl2 to catalyse addition of RX (organohalide, e.g. PhBr)
Negishi
Kumada
Sonogashira
Use of Sonogashira coupling in enediyne synthesis
- Synthesis of calicheamicin
- calicheamicin is an enediyne antibiotic and anti-tumour drug: the enediyne "warhead" or "business end" works by doing a Bergman cyclization
Hartwig-Buchwald coupling
- "Amination", R-X → R-NH-R′
- RX + R′NH2 → RNHR′ + HX
- Catalysed by 0PdL2
- [R′H2N+PdL2R][X−] deprotonated
sp³ hybridised carbon in the oxidative addition process
Heck reaction
- Heck reaction
- Named after Richard Heck who developed the reaction in the 1970s
Other interactions of alkenes with Pd(II)
Cyclopropanation using electrophilic carbene complexes
- Cyclopropanation using electrophilic carbene complexes
- Carbene complexes are often called carbenoids
- Cyclopropanes are found in nature as pyrethrins, and are produced synthetically as pyrethroid insecticides
- Use ethyl diazoacetate as a source of :CEt2 (or more generally use R2CN2 as a source of :CR2)
- Use an alkene as a source of R2C•—•CR2
- R2C: + R2C•—•CR2 → cyclo-(R2C)3, i.e. a cyclopropane
- Cu or Rh catalyst
Cilastatin synthesis
- Example of a Cu-catalysed asymmetric cyclopropanation: synthesis of cilastatin
Ring-closing metathesis
- Ring-closing metathesis
- catalysed by Grubbs' first generation catalyst, Cl2(Cy3P)Ru=CHPh