Nitrogen separating mixtures with

A mixture of l-(r-Boc)indol-2-yl-tri- -butylstannanc (1.2 mmol) and 4-bromo-benzonitrile (1.0 mmol) and Pd(PPh3)2C , (0.02 mmol) in dry dioxane (5 ml) was heated at I00°C overnight under nitrogen. The reaction mixture was cooled, diluted with EtOAc and stirred for 15 min with 15% aq. KF. The precipitate was removed by filtration and washed with EtOAc. The EtOAc layer was separated, washed with brine, dried (Na2S04) and concentrated. The residue was purified by chromatography on silica. The yield was 66%. 

A solution of 0.11 mol of 1.5M butyllithium in hexane is added to 30 mL of THF under a layer of argon or nitrogen at —78 C, followed by 0.10 mol of (4S,5/ )-1-allyl-3,4-dimcthyl-5-phenyl-2-imidazolidinone in 75 mL of THF. After 25 min, a solution of 0.11 mol of chlorotris(diethylamino)titanium in 30 mL of THF is introduced. The mixture is stirred at — 20 °C for 45 min, then 0.11 mol of the aldehyde or ketone in 10 mL of THF is added. After 2 h. 20 mL of water and 200 mL of diethyl ether are added. The ethereal solution is separated, washed with 20 mL of 10% aq NaHS03 followed by 20 mL of water, dried over Na2S04 and concentrated, whereupon the product crystallizes. Diastereomerically pure samples are prepared by recrystallization from hexane or hexane/ethyl acetate. 

N-benzylaniline with phosgene, and then with sodium azide to produce carbonyl azide 52. On heating, nitrogen is evolved and a separable mixture of nitrene insertion product 53 and the desired ketoindazole 54 results. The latter reaction appears to be a Curtius-type rearrangement to produce an N-isocyanate (54a), which then cyclizes. Alkylation of the enol of 54... 

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