(Z)-4-Phenylbutan-2-yl acetate → 1-Phenyl-3-acetoxybutane

HRID 1419602Notes

Reaction equation

HRID 1419602 reaction equation
[C:1]([O:4][C:5]([C:7]#[C:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)=[CH2:6])(=[O:3])[CH3:2].[H][H].C(OC(/C=C\C1C=CC=CC=1)C)(=O)C>C1COCC1.F[B-](F)(F)F.C1([Rh+]C2CCCCC=CC=2)CCCCC=CC=1>[C:1]([O:4][CH:5]([CH2:7][CH2:8][C:9]1[CH:10]=[CH:11][CH:12]=[CH:13][CH:14]=1)[CH3:6])(=[O:3])[CH3:2]

Participants

6

Reactant 3

HCID 10420030(Z)-4-Phenylbutan-2-yl acetateHCID 158644744-Phenylbut-1-en-3-yn-2-yl acetateHCID 178418361HCID 178418361, compound

Product 1

HCID 615171-Phenyl-3-acetoxybutane

Reagents, catalysts & solvents 2

HCID 178420271HCID 178420271, compoundCatalystHCID 8028TetrahydrofuranSolvent

Procedure

This reaction was performed as in Example 1 with bis(cyclooctadienyl)rhodium tetrafluoroborate (10 mg; 0.025 mmol; 0.02 equiv), R,R-1,2-bis(2,5-dimethylphospholano)benzene (6, R"=CH3 ; 9 mg; 0.03 mmol; 0.024 equiv) and 4-phenylbut-1-en-3-yn-2-yl acetate (3b; 233 mg; 1.25 mmol) in 10 mL of degassed THF until hydrogen uptake ceased to afford 0.25 g of crude product. 1H NMR analysis indicated Z-4-phenyl-3-buten-2-yl acetate (5b) as the sole product, and reduction of the olefin to afford 4-phenyl-2-butyl acetate followed by chiral GC analysis and comparison to the racemate and authentic R-4-phenyl-2-butyl acetate indicated 97.8% ee for R-Z-4-phenyl-3-buten-2-yl acetate. Further investigation indicated a bimodal reduction, with 4-phenylbut-1-en-3-yn-2-yl acetate initially chemoselectively and enantioselectively reduced to 4-phenylbut-3-yn-2-yl acetate (4b), which was then more slowly reduced to Z-4-phenyl-3-buten-2-yl acetate (5b).

Workup

  1. customto afford 0.25 g of crude product

Sources & evidence

ORD record
ord-6230ae31dbcc46fc9e7f49f27c6132fd
Source dataset
uspto-grants-1999_03
Patent number
US05886214

Reaction notes

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