Hot Topics en Hypes

1
Hot Topicsen Hypes

• in organometallic chemistry

2
Hot Topics

• Ideal conversions with (nearly) incompatible
  requirements
• C-H activation
• and other "all-in-one" conversions
• Selective oxidations
• Anti-Markovnikov water addition
• (Co)polymerization of functionalized olefins
• Chiral conversions
• Mechanisms / models of enzymes

3
Hypes

• Everything "BIO" and "NANO"
• Buckyballs, buckytubes
• Supramolecular chemistry
• Materials

4
C-H activation

• Problems
• C-H bond is least reactive bond
• Product is usually more reactivethan starting
  material
• Þ further oxidation
• Product is always better donorthan starting
  material
• Þ product inhibition

5
C-H activation

• This will not work

6
C-H activation

• This does work

B-B bond weak B-H and B-C strong product
hardlycoordinating
7
C-H activation

• A real example

Electrophilic attack on C-H bond (?)
8
CH4 to CH3OHhow does industry do it?

• "hot pipes"

9
CH4 to CH3OHhow does nature do it?(we think)
MMO "methane mono-oxygenase"
10
C-H activation

• C-H activation for CH4 CH3OH via homogeneous
  catalysis is "useless"
• selective conversion van non-activated C-H bonds
  in larger molecules is highly desirable
• nature does this through "shape selectivity" with
  e.g. cytochrome P450
• zeolites sometimes work quite well

11
How can you studyC-H activation?

• "microscopic reversibility"
• activation of more reactive C-H bonds
• e.g. aromatic Csp2-H bonds

12
Selective oxidation

• Epoxidation
• does not work for other olefins
• (allylic C-H bonds are too reactive)

13
Selective oxidation

• Aldehydes / ketones

14
Selective oxidation

• Desired
• Current process hydroformylation

15
Anti-Markovnikov water addition

• Desired
• Current process via hydroformylation

16
Anti-Markovnikov water addition

• A possible organometallic route

17
(Co)polymerization of functionalized olefins

• Desired
• Problem

18
(Co)polymerisation of functionalized olefins

• Possible solutions
• Late transition metal complexes
• b.v. Ni/Pd Brookhart
• Protection of functional group
• Fictionalization after polymerization

19
Chiral conversions

• Noyori / Knowles / Sharpless
• Precise tuning needed for every new reaction
• combinatorial catalysis?
• Few general principles
• Many "standard" chiral ligands

20
Chiral conversions