Reaction #2033

Reaction equation

triphenylphosphine

Br2

4,7-decadien-1-ol

NaHCO3

→

(4Z,7Z)-1-bromo-4,7-decadiene

Yield 32.0%

Solvents

CH2Cl2

CH2Cl2

CH2Cl2

water

Conditions

Workup

1. 1
   OtherInto the slightly yellow suspension that formed
2. 2
   workup.ADDITIONthe crude mixture of 4
3. 3
   workup.STIRRINGAfter stirring for 1 hour
4. 4
   ExtractionThe mixture was extracted with pentane
5. 5
   workup.WAITwere stored overnight in a freezer
6. 6
   OtherIn this way, triphenylphosphine oxide could be crystallized
7. 7
   Otherremoved by filtration
8. 8
   workup.DISTILLATIONColumn chromatography followed by distillation at reduced pressure
9. 9
   Otherafforded 5 (3.48 g, 32% yield
10. 10
    Other=80°-85° C./2.5 torr

Procedure

A solution of triphenylphosphine (20.9 g, 80 mmol) in CH2Cl2 (100 ml) was treated with Br2 (7.8 g, 49 mmol) in CH2Cl2 (15 mL, 0° C.) and the mixture was stirred at room temperature for 20 min. Into the slightly yellow suspension that formed, the crude mixture of 4 and 4Z,7Z)-4,7-decadien-1-ol (12.4 g) in CH2Cl2 (15 ml) was added dropwise. After stirring for 1 hour, a solution of saturated NaHCO3 (50 mL) and water (50 ml) were added. The mixture was extracted with pentane and combined extracts were stored overnight in a freezer. In this way, triphenylphosphine oxide could be crystallized and removed by filtration. Column chromatography followed by distillation at reduced pressure afforded 5 (3.48 g, 32% yield based on 1 of b.p. =80°-85° C./2.5 torr. 1H NMR (200 MHz) δ: 5.37 (m, 4H, CH=CH), 3.41 (t, J=6.6, 6.6 Hz, 2H, CH2 --Br), 2.80 (dd, J=6.4, 6.5 Hz, 2H, =CH--CH2 --CH=), 2.21 (dt, J=7.0, 6.9, 6.8, 6.9 Hz, 2H, CH2 -3), 2.07 (dq, J=7.4 Hz, CH2 -9), 1.91 (tt, J=6.7, 6.6, 7.0, 7.0, 2H, CH2 -2), 0.97 (t, J=7.5, 7.5 Hz, 3H, CH3). 13C NMR (100.6 MHz) δ: 132.1 (8), 129.8 (5), 127.6 (7), 127.0 (4), 33.4 (1), 32.5 (2), 25.6 (3), 25.5 (6), 20.6 (9), 14.3 (10). MS [EI, m/z (%)] 218 (M+, 15), 216 (17), 137 (6), 109 (13), 107 (18), 96 (14), 95 (78), 82 (18), 81 (74), 79 (22), 68 (27), 67 (100), 55 (17), 53 (15), 42 (11), 41 (38), 40 (40).

Source