Reaction SMILES: [F:1][C:2]1[CH:7]=[CH:6][C:5]([N:8]2[C:16]3[CH:15]=[C:14]4[CH2:17][CH2:18][CH2:19][C@H:20]5[CH2:25][C@:24]([O:30][Si:31]([CH2:36][CH3:37])([CH2:34][CH3:35])[CH2:32][CH3:33])([C:26]([F:29])([F:28])[F:27])[CH2:23][CH2:22][C@:21]5([C:38]#N)[C:13]4=[CH:12][C:11]=3[CH:10]=[N:9]2)=[CH:4][CH:3]=1.[F:40][C:41]1[CH:46]=[CH:45][C:44]([N:47]2[C:55]3[CH:54]=[C:53]4[CH2:56][CH2:57][CH2:58][C@@H:59]5[CH2:64][C@@:63]([O:69][Si:70]([CH2:75][CH3:76])([CH2:73][CH3:74])[CH2:71][CH3:72])([C:65]([F:68])([F:67])[F:66])[CH2:62][CH2:61][C@@:60]5([C:77]#N)[C:52]4=[CH:51][C:50]=3[CH:49]=[N:48]2)=[CH:43][CH:42]=1.CC(C[AlH]CC(C)C)C>C1(C)C=CC=CC=1>[F:1][C:2]1[CH:7]=[CH:6][C:5]([N:8]2[C:16]3[CH:15]=[C:14]4[CH2:17][CH2:18][CH2:19][C@H:20]5[CH2:25][C@:24]([O:30][Si:31]([CH2:32][CH3:33])([CH2:36][CH3:37])[CH2:34][CH3:35])([C:26]([F:29])([F:27])[F:28])[CH2:23][CH2:22][C@:21]5([CH:38]=[O:69])[C:13]4=[CH:12][C:11]=3[CH:10]=[N:9]2)=[CH:4][CH:3]=1.[F:40][C:41]1[CH:46]=[CH:45][C:44]([N:47]2[C:55]3[CH:54]=[C:53]4[CH2:56][CH2:57][CH2:58][C@@H:59]5[CH2:64][C@@:63]([O:69][Si:70]([CH2:71][CH3:72])([CH2:75][CH3:76])[CH2:73][CH3:74])([C:65]([F:68])([F:66])[F:67])[CH2:62][CH2:61][C@@:60]5([CH:77]=[O:30])[C:52]4=[CH:51][C:50]=3[CH:49]=[N:48]2)=[CH:43][CH:42]=1
Reactant: CC[Si](CC)(CC)O[C@@]1(C(F)(F)F)CC[C@]2(C#N)c3cc4cnn(-c5ccc(F)cc5)c4cc3CCC[C@H]2C1
Reactant: CC[Si](CC)(CC)O[C@]1(C(F)(F)F)CC[C@@]2(C#N)c3cc4cnn(-c5ccc(F)cc5)c4cc3CCC[C@@H]2C1
Agent: CC(C)C[AlH]CC(C)C
Solvent: Cc1ccccc1
Product: CC[Si](CC)(CC)O[C@@]1(C(F)(F)F)CC[C@]2(C=O)c3cc4cnn(-c5ccc(F)cc5)c4cc3CCC[C@H]2C1
Product: CC[Si](CC)(CC)O[C@]1(C(F)(F)F)CC[C@@]2(C=O)c3cc4cnn(-c5ccc(F)cc5)c4cc3CCC[C@@H]2C1
Temperature: 0 °C
Reaction time: 1 h
Yield: 94 %

Procedure:
A solution of (3R,4aR,12bS)-9-(4-fluorophenyl)-3-((triethylsilyl)oxy)-3-(trifluoromethyl)-1,2,3,4,4a,5,6,7,9,12b-decahydrobenzo[6,7]cyclohepta[1,2-f]indazole-12b-carbonitrile; compound with (3S,4aS,12bR)-9-(4-fluorophenyl)-3-((triethylsilyl)oxy)-3-(trifluoromethyl)-1,2,3,4,4a,5,6,7,9,12b-decahydrobenzo[6,7]cyclohepta[1,2-f]indazole-12b-carbonitrile (39, R1=4-Fluorophenyl, R3=Trifluoromethyl) (600 mg, 1.08 mmol) in Toluene (24 mL) was cooled to about 0° C. and DIBAL-H (1M solution in cyclohexane, 6.5 mL, 6.5 mmol) was added dropwise while maintaining the reaction temperature below about 1° C. The reaction was stirred at about 0° C. for about 1 h. The reaction was quenched by addition of 6% HOAc in sat. aq. NaOAc (25 mL) while maintaining the reaction temperature below 5° C. The mixture was allowed to warm to rt, water (10 mL) was added and stirring was continued for about 2 h. The layers were separated and the organic layer was stirred with sat. aq. NH4Cl (25 mL) for about 2 h. The organic layer was dried with Na2SO4, filtered and concentrated to a waxy solid (730 mg). The crude was purified on silica gel (40 g) using a gradient of 5-20% EtOAc in heptane. Product fractions were combine and concentrated under reduced pressure to yield (3R,4aR,12bS)-9-(4-fluorophenyl)-3-((triethylsilyl)oxy)-3-(trifluoromethyl)-1,2,3,4,4a,5,6,7,9,12b-decahydrobenzo[6,7]cyclohepta[1,2-f]indazole-12b-carbaldehyde; compound with (3S,4aS,12bR)-9-(4-fluorophenyl)-3-((triethylsilyl)oxy)-3-(trifluoromethyl)-1,2,3,4,4a,5,6,7,9,12b-decahydrobenzo[6,7]cyclohepta[1,2-f]indazole-12b-carbaldehyde (40, R1=4-Fluorophenyl, R3=Trifluoromethyl) as a viscous oil (566 mg, 94%); LC/MS, method 4, Rt=2.58 min, MS m/z 561 (M+H)+, 1H NMR (400 MHz, DMSO) δ 9.37 (d, J=1.9 Hz, 1H), 8.32 (d, J=0.9 Hz, 1H), 8.04 (s, 1H), 7.82-7.77 (m, 2H), 7.63 (s, 1H), 7.44-7.37 (m, 2H), 3.00-2.91 (m, 1H), 2.71-2.58 (m, 1H), 2.29-1.90 (m, 6H), 1.86-1.58 (m, 4H), 1.36-1.21 (m, 1H), 0.99-0.90 (m, 9H), 0.67-0.58 (m, 6H).