Lithium hydridotris(3-methylbutan-2-yl)borate(1-) → 1,1-Dimethylethyl N-((1S,3R)-3-hydroxycyclopentyl)carbamate

Temperatur

-78 °C

A 1M solution of lithium tris(1,2-dimethylpropyl)borohydride in tetrahydrofuran (1.99 ml) was diluted with tetrahydrofuran (3 ml), cooled to -78° C. and treated dropwise with a solution of (S)-(3-oxocyclopentyl)carbamic acid 1,1-dimethylethyl ester (0.38 g,1.66 mmol) in dry tetrahydrofuran (2 ml) at 0° C. The reaction was stirred for 2h at -78° C. then allowed to warm to room temperature over 1h. Water (2 ml) was added dropwise then the mixture was diluted with water (20 ml) and ethyl acetate (30 ml). The organic phase was washed with water (20 ml), dried (MgSO4) and evaporated to give impure product which was purified by chromatography on flash silica eluting initially with 15% ethyl acetate in cyclohexane and progressing to neat ethyl acetate. Early fractions gave (1S-cis)-(3-hydroxycyclopentyl)carbamic acid 1,1-dimethylethyl ester (0.16 g) as an oil, nmr (d,CDCl3) 1.43(s,9H), 1.50-2.10(m,6H), 3.97-4.10(m,1H), 4.32-4.40(m,1~H), 5.00-5.12(m,1H).

1. temperatureto warm to room temperature over 1h
2. washThe organic phase was washed with water (20 ml)
3. dry with materialdried (MgSO4)
4. customevaporated
5. customto give impure product which
6. customwas purified by chromatography on flash silica eluting initially with 15% ethyl acetate in cyclohexane and progressing to neat ethyl acetate

ORD-Eintrag

ord-f2111bcd4996469ca131854909b93bd4

Quelldatensatz

uspto-grants-1999_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05925624