Isobutyltriphenylphosphonium bromide → trans-N-Boc-2-methyl-6-(1-isopentenyl)piperidine

Temperature

-30 °C

A suspension of isobutyltriphenylphosphonium bromide (10.58 g, 26.5 mmol) in 42 mL of THF was cooled to −30° C. and treated with n-BuLi (12.2 mL, 26.88 mmol) dropwise. The deep red solution was slowly warmed to 0° C., stirred for 30 min, and then cooled to −78° C. The ylide was treated with a solution of trans-N-Boc-2-Methyl-6-Piperidinecarboxaldehyde (4.00 g, 18.93 mmol) in 6 mL of THF, and the mixture was slowly warmed to room temperature. The mixture was diluted with water, and the organic layer was separated. The aqueous layer was extracted with ether and the combined extracts were dried over K2CO3 and then concentrated to give a crude product as an oil. Chromatography on silica with 5% EtOAc/hexane afforded 3.2 g (63%) of the product which was homogeneous by TLC analysis. 1H NMR (250 MHz) δ 5.41-5.14 (m, 2H), 4.62-4.58 (m, 1H), 4.05-4.01 (m, 1H), 2.69-2.68 (m, 1H), 1.90-1.38 (m, 15H), 1.23-1.20 (d, 3H), 0.93-0.87 (t, 6H); 13C NMR (62.7 MHz) 156.1 (s), 136.8 (s), 129.8 (s), 79.0 (s), 49.1 (s), 47.5 (s), 28.7 (s), 28.5 (s), 27.9 (s), 26.6 (s), 23.3 (s), 23.0 (s), 20.2 (s), 15.1 (s) ppm.

1. temperatureThe deep red solution was slowly warmed to 0° C.
2. temperaturecooled to −78° C
3. temperaturethe mixture was slowly warmed to room temperature
4. customthe organic layer was separated
5. extractionThe aqueous layer was extracted with ether
6. dry with materialthe combined extracts were dried over K2CO3
7. concentrationconcentrated
8. customto give a crude product as an oil

ORD record

ord-f54eedfc12d34ffd92a16d57ed019280

Source dataset

uspto-grants-2012_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08168657B2