rac-(7aR,11aR)-N-(diphenylmethylene)-11a-vinyl-7,7a,8,10,11,11a-hexahydro-6H-spiro[dibenzo[b,d]oxepine-9,2'-[1,3]dioxolan]-3-amine → rac-(7aR,11aS)-11a-ethyl-7,7a,8,10,11,11a-hexahydro-6H-spiro[dibenzo[b,d]oxepine-9,2'-[1,3]dioxolan]-3-amine

Participants

Reaction Steps

A 500 mL round-bottom flask equipped with a 3-way stopcock was charged with rac-(7 aS,11aS)—N-(diphenylmethylene)-11a-vinyl-7,7a,8,10,11,11a-hexahydro-6H-spiro[dibenzo[b,d]oxepine-9,2′-[1,3]dioxolan]-3-amine (85, R2=Vinyl) (17.7 g, 38.0 mmol) and 10% palladium on carbon (2.02 g, 1.90 mmol) in EtOH (190 mL). The vessel was evacuated and backfilled with hydrogen from a balloon and the resulting suspension was allowed to stir at rt for about 22 h. The mixture was filtered through a pad of Celite® using rinses of EtOAc (3×25 mL). The combined filtrates were concentrated under reduced pressure and the resulting crude material was purified on silica gel (330 g, eluted with 0 to 50% EtOAc in heptane). Collection and concentration of the appropriate fractions gave rac-(7aR,11aS)-11a-ethyl-7,7a,8,10,11,11a-hexahydro-6H-spiro[dibenzo[b,d]oxepine-9,2′-[1,3]dioxolan]-3-amine (86, R2=Ethyl) (11.24 g, 97%). LC/MS, method 3, 2.14 min, MS m/z 304 (M+H)+. 1H NMR (400 MHz, CDCL3) δ 7.00 (d, J=8.4 Hz, 1H), 6.56-6.45 (m, 2H), 5.34 (bs, 1H), 4.21-4.11 (m, 1H), 3.98-3.85 (m, 4H), 3.72-3.60 (m, 1H), 2.69-2.56 (m, 1H), 2.34-2.24 (m, 1H), 2.19-2.03 (m, 2H), 1.93-1.80 (m, 1H), 1.79-1.65 (m, 2H), 1.64-1.36 (m, 4H), 1.35-1.25 (m, 1H), 0.61 (t, J=7.4 Hz, 3H).

Provenance & Evidence