Reaction Steps
In a 1 dram vial under nitrogen were combined (2R)-1-[(1R)-1-[bis(1,1-dimethylethyl)phosphino]ethyl]-2-(dicyclohexylphosphino)ferrocene (CAS#158923-11-6) (2.101 mg, 3.79 μmol), palladium(II) acetate (0.851 mg, 3.79 μmol) and dry DME (0.5 ml). The contents of the vial were stirred for 10 min, and were then added all at once to a separate mixture of 2-bromopyridine (0.012 g, 0.076 mmol) and sodium tert-butoxide (0.032 g, 0.333 mmol) in dry DME (0.5 mL) contained in a separate 1 dram vial. The resulting mixture was allowed to stir very briefly (1 min) before TBDMSCl (0.025 g, 0.167 mmol) was added. The vial was shaken briefly, and solid methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(2-aminoethylamino)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)benzoate bis HCl salt (0.050 g, 0.076 mmol) was added in one portion. A mild exotherm resulted upon the final addition. The mixture was heated to 110° C. for 15 min. LCMS indicated essentially complete consumption of starting material. To the mixture was added water (0.5 mL) and methanol (1.5 mL) and the resulting mixture was stirred for 2 days. Purification of the crude mixture by reverse phase preparative HPLC using Prep HPLC Method 6 gave the title compound (0.0092 g, 13.1% yield) as a beige powder bis TFA salt. LCMS: m/e 650.4 (M+H)+, 3.76 min (method 16). 1H NMR (500 MHz, 1:1 mixture of CDCl3 and MeOD, MeOD lock) δ ppm 8.01 (d, J=4.9 Hz, 1H), 7.95-7.88 (m, J=8.2 Hz, 2H), 7.72 (t, J=7.3 Hz, 1H), 7.23-7.16 (m, J=8.2 Hz, 2H), 6.92 (d, J=8.2 Hz, 1H), 6.85 (t, J=6.3 Hz, 1H), 5.29 (d, J=4.9 Hz, 1H), 4.86 (s, 1H), 4.74 (br. s., 1H), 3.90-3.72 (m, 2H), 3.23-3.14 (m, 1H), 2.78-2.67 (m, 1H), 2.17-2.04 (m, 2H), 2.03-1.82 (m, 5H), 1.73 (s, 3H), 1.71-1.66 (m, 1H), 1.65-1.46 (m, 6H), 1.45-1.22 (m, 9H), 1.21-1.09 (m, 1H), 1.06 (s, 3H), 0.99 (br. s., 3H), 0.98 (br. s., 3H), 0.94 (s, 3H), 0.93 (br. s., 3H), 0.91-0.84 (m, J=6.7, 3.4 Hz, 1H).
