h under an argon atmosphere the mixture was cooled to 0 u00b0 c treated with a solution of 4 bromo butoxy tert butyl diphenyl silane b 1 56 g 4 mmol in dmf 10 ml and stirred at 0 u00b0 c for an additional 3 hours the solvents were removed under reduced pressure and the residue was dissolved in etoac 150 ml and poured into a separatory funnel the organic layer was washed with 0 1 m naoh 5 u00d7 50 ml h 2 o 50 ml 0 1 m khso 4 and brine 50 ml and the dried with mgso 4 after removal of the solvent the residue was chromatographed on silicagel hexane etoac 10 1 to yield 0 588 g 24 the product was identified by electrospray mass spectrometry esi ms mh calculated 457 26 found 457 8 tbaf 1 6 ml 1 586 mmol was added to o 4 tert butyl diphenyl silanyloxy butyl n methyl n boc hydroxylamine c 588 mg 1 22 mmol dissolved in dry thf 20 ml the reaction was stirred over night under argon nh 4 cl saturated was added to the solution 10 ml u00d7 3 and the thf was evaporated the solution was extracted with dcm the organic phase was dried na 2 so 4 and evaporated the residue was chromatographed hexane etoac 1 1 on silicagel to give 0 170 g 63 the product was analyzed by hplc column phenomenex luna 3 u03bc c18 2 4 6 u00d7 50 mm detection 214 nm gradient 50 100 b over 10 min where a h 2 o 0 1 tfa and b acetonitrile 0 1 tfa flow rate 2 ml min rt 2 70 min further confirmation was carried out by nmr analysis to a ice bath.