Cyclopropylacetylene → (1S,4R)-N-(4-chloro-2-((S)-4-cyclopropyl-1,1,1-trifluoro-2-hydroxybut-3-yn-2-yl)phenyl)-4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carboxamide

Participants

Reaction Steps

2.5 M n-Butyllithium (14.8 mL, 37.16 mmol) was added slowly to a solution of cyclopropyl acetylene (2.46 g, 37.16 mmol) in tetrahydrofuran (20 mL) in an ice-salt-bath under argon, and then (1S,4R)-N-(4-chloro-2-(2,2,2-trifluoroacetyl)phenyl)-4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carboxamide(9, 5 g, 12.39 mmol) was added. The reaction mixture was stirred for 0.5 hour. The reaction was quenched with 10% citric acid aqueous, the mixture was extracted with ethyl acetate and the two layers were separated. The organic layer was evaporated to dryness to give crude oil which was further crystallized with ethyl acetate and petroleum ether to give (1S,4R)-N-(4-chloro-2-((S)-4-cyclopropyl-1,1,1-trifluoro-2-hydroxybut-3-yn-2-yl)phenyl)-4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carboxamide (10) as a white or off-white powder. 1H NMR spectrum of the product was identical to that of Example 5.

Provenance & Evidence