3-Bromopyridine → (S)-N-((S)-2-(tert-butyldimethylsilyloxy)-1-(pyridin-3-yl)ethyl)-2-methylpropane-2-sulfinamide

Participants

Reaction Steps

To a solution of toluene (50 mL) cooled to −78° C. was added 2.5 M butyllithium in hexanes (6.31 mL, 15.1 mmol) and the reaction mixture was stirred until the temperature returned to −78° C. 3-Bromopyridine (1.88 g, 11.9 mmol) in toluene (5 mL) was added to the reaction mixture a rate such that the temperature never went above −65° C., and then the reaction was stirred at −78° C. for 1 hour. (S,E)-N-(2-(tert-Butyldimethylsilyloxy)ethylidene)-2-methylpropane-2-sulfinamide (3.00 g, 10.8 mmol) in toluene (1 mL) was added to the reaction mixture at a rate such that the temperature did not exceed −70° C., and then the reaction was stirred at −78° C. for 2 hours. To the −78° C. solution was added brine and the mixture partitioned between ETOAc/water. The organic layer was washed with brine, dried (phase separator silicone treated filter paper), concentrated and purified on silica gel (15-80% EtOAc in DCM) to provide (S)—N—((S)-2-(tert-butyldimethylsilyloxy)-1-(pyridin-3-yl)ethyl)-2-methylpropane-2-sulfinamide (0.862 g, 22% yield) as a yellow oil.

Provenance & Evidence