1 YSU YSU Organolithiums YSU YSU 2 Organomagnesium compounds - - PDF document

▶
1
SMART_READER_LITE
LIVE PREVIEW

1 YSU YSU Organolithiums YSU YSU 2 Organomagnesium compounds - - PDF document

Feb 09, 2024 345 likes •506 views

Radical Carbon Carbon chemistry electrophiles nucleophiles YSU YSU Cyclopropyl Vinyl sodium Diethyl magnesium lithium Methylmagnesium iodide Diethylaluminum chloride YSU YSU 1 YSU YSU Organolithiums YSU YSU 2 Organomagnesium

slide-1
SLIDE 1

1

YSU YSU

Radical chemistry Carbon electrophiles Carbon nucleophiles Cyclopropyl lithium Vinyl sodium Diethyl magnesium

YSU YSU

Methylmagnesium iodide Diethylaluminum chloride

slide-2
SLIDE 2

2

YSU YSU YSU YSU

Organolithiums

slide-3
SLIDE 3

3

YSU YSU

Organomagnesium compounds – Grignard reagents

CH3Li, (CH3)3CLi, n‐BuLi are extremely powerful bases

YSU YSU

Convenient preparation of Lithium Diisopropylamide (LDA)

slide-4
SLIDE 4

4

Lab Experiment Grignard Reagent Preparation

  • Glassware must be clean and dry

YSU YSU

  • Dry with the “heat gun”
  • Cool then begin experiment

Be careful to use the right ether!

YSU YSU

slide-5
SLIDE 5

5

Carbonyl polarization:

YSU YSU

Grignard polarization: Carbonyl polarization:

YSU YSU

Grignard polarization:

slide-6
SLIDE 6

6

New Mechanism: Nucleophilic Addition

YSU YSU

Most often followed by a quench with acid:

Overall Sequence: Nucleophilic Addition then quench

YSU YSU

Very versatile alcohol synthesis Works well with most aldehydes & ketones

slide-7
SLIDE 7

7

Example:

YSU YSU

1 2 3 4 5 6 7 PPM 1 2 3 4 5 6 7 PPM

Starting material Product

Starting material Product Product IR: 3200 cm‐1

Example:

Cl

  • 1. Mg, ether
  • 2. CH3CHO
  • 3. H3O+

OH

YSU YSU

10 20 30 40 50 60 70 PPM 10 20 30 40 50 60 70 80 PPM

Starting material Product

slide-8
SLIDE 8

8

S i i l P d Product MS: M+ = 254 YSU YSU

1 2 3 PPM 1 2 3 4 5 6 7 PPM

Starting material Product H3C C C H

  • 1. NaNH2
  • 2. H2C=O
  • 3. H3O+

H3C C C CH2OH H C YSU YSU O

H3C C C Li 1.

  • 2. H3O+

OH C C H3C

slide-9
SLIDE 9

9

Target molecule Precursor molecules

YSU YSU

(synthetic equivalent)

YSU YSU

2‐deoxy‐D‐ribose

D‐mannopyranose

slide-10
SLIDE 10

10

YSU YSU (synthetic equivalent)

Example:

YSU YSU Either will work on paper (i.e. on exams)

slide-11
SLIDE 11

11

Example:

OH MgBr H O + YSU YSU O H BrMg + OH MgBr O H + Br YSU YSU Br

  • 1. Mg, THF

2. O H

  • 3. H3O+

OH

slide-12
SLIDE 12

12

YSU YSU Retrosynthesis: Synthesis:

OH O H3CO 2 CH3MgBr + CH B

  • 1. Mg, THF

OH

YSU YSU Synthesis: Also possible:

CH3Br

  • 2. PhCO2CH3 (0.5 eq)
  • 3. H3O+

H3C H3C OH O + MgBr

slide-13
SLIDE 13

13

Will cover 14.11 in Special Topics at end of semester

YSU YSU Iodomethyl zinc iodide YSU YSU

Simmons‐Smith reaction

slide-14
SLIDE 14

14

Will cover sections 14.13 – 14.17 in Special Topics at end of semester

YSU YSU