Reaction SMILES: [CH3:1][CH2:2][CH:3]([C@H:5]1[O:10][C@:9]2([O:15][C@@H:14]3[CH2:16][CH:17]=[C:18]([CH3:61])[C@@H:19]([O:40][C@@H:41]4[O:46][C@@H:45]([CH3:47])[C@H:44]([O:48][C@@H:49]5[O:54][C@@H:53]([CH3:55])[C@H:52]([OH:56])[C@@H:51]([O:57][CH3:58])[CH2:50]5)[C@@H:43]([O:59][CH3:60])[CH2:42]4)[C@@H:20]([CH3:39])[CH:21]=[CH:22][CH:23]=[C:24]4[CH2:25][O:26][C@@H:27]5[C@H:32]([OH:33])[C:31]([CH3:34])=[CH:30][C@@H:29]([C:35]([O:37][C@@H:12]([CH2:13]3)[CH2:11]2)=[O:36])[C@:28]45[OH:38])[CH:8]=[CH:7][C@@H:6]1[CH3:62])[CH3:4]>C1(C)C=CC=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.[Cl-].[Rh]>[CH3:1][CH2:2][C@@H:3]([C@H:5]1[O:10][C@:9]2([O:15][C@@H:14]3[CH2:16][CH:17]=[C:18]([CH3:61])[C@@H:19]([O:40][C@@H:41]4[O:46][C@@H:45]([CH3:47])[C@H:44]([O:48][C@@H:49]5[O:54][C@@H:53]([CH3:55])[C@H:52]([OH:56])[C@@H:51]([O:57][CH3:58])[CH2:50]5)[C@@H:43]([O:59][CH3:60])[CH2:42]4)[C@@H:20]([CH3:39])[CH:21]=[CH:22][CH:23]=[C:24]4[CH2:25][O:26][C@@H:27]5[C@H:32]([OH:33])[C:31]([CH3:34])=[CH:30][C@@H:29]([C:35]([O:37][C@@H:12]([CH2:13]3)[CH2:11]2)=[O:36])[C@:28]45[OH:38])[CH2:8][CH2:7][C@@H:6]1[CH3:62])[CH3:4]
Reactant: CCC(C)[C@H]1O[C@]2(C=C[C@@H]1C)C[C@@H]1C[C@@H](CC=C(C)[C@@H](O[C@H]3C[C@H](OC)[C@@H](O[C@H]4C[C@H](OC)[C@@H](O)[C@H](C)O4)[C@H](C)O3)[C@@H](C)C=CC=C3CO[C@@H]4[C@H](O)C(C)=C[C@@H](C(=O)O1)[C@]34O)O2
Agent: [Rh]
Agent: CCC(C)[C@H]1O[C@]2(C=C[C@@H]1C)C[C@@H]1C[C@@H](C/C=C(\C)[C@@H](O[C@H]3C[C@H](OC)[C@@H](O[C@H]4C[C@H](OC)[C@@H](O)[C@H](C)O4)[C@H](C)O3)[C@@H](C)/C=C/C=C3\CO[C@@H]4[C@H](O)C(C)=C[C@@H](C(=O)O1)[C@]34O)O2
Agent: CC[C@H](C)[C@H]1O[C@]2(CC[C@@H]1C)C[C@@H]1C[C@@H](C/C=C(\C)[C@@H](O[C@H]3C[C@H](OC)[C@@H](O[C@H]4C[C@H](OC)[C@@H](O)[C@H](C)O4)[C@H](C)O3)[C@@H](C)/C=C/C=C3\CO[C@@H]4[C@H](O)C(C)=C[C@@H](C(=O)O1)[C@]34O)O2
Solvent: Cc1ccccc1
Product: CC[C@H](C)[C@H]1O[C@]2(CC[C@@H]1C)C[C@@H]1C[C@@H](CC=C(C)[C@@H](O[C@H]3C[C@H](OC)[C@@H](O[C@H]4C[C@H](OC)[C@@H](O)[C@H](C)O4)[C@H](C)O3)[C@@H](C)C=CC=C3CO[C@@H]4[C@H](O)C(C)=C[C@@H](C(=O)O1)[C@]34O)O2
Temperature: 40 °C

Procedure:
39 g of Avermectin Bla is dissolved in 1540 ml of toluene and introduced into a 4 liter stirred autoclave. To this is added 3.9 g of tris(triphenylphosphine)rhodium (I) chloride (Wilkinson's catalyst). A hydrogenation pressure of 40 psi and a temperature of 40° C. is maintained with stirring for 41/2 hours. At the end of this period liquid chromatographic analysis indicates 98% yield of dihydro avermectin Bla with 1.5% of tetrahydro avermectin Bla. The toluene is removed by evaporation in vacuo and the dark red gum is dissolved in ethanol at a rate of 4 ml of ethanol per gram of product. Formamide at a rate of 10 ml per gram of product is added and the solution heated on the steam bath to 40°-50° while adding water at a rate of 2 ml per gram of product. After crystallization commences the heat is removed and the solution allowed to cool slowly with stirring overnight. The solid is filtered off and washed with a mixture 3 parts water and 1 part ethanol and dried in vacuo overnight. The solids are dissolved in 150 ml of ethanol and warmed to 35°-40° C. on the steam bath. Water, 150 ml is added slowly with stirring. When solution is complete at 35° C. the heat is removed and the solution allowed to cool slowly overnight. The crystals are removed by filtration and washed with aqueous ethanol and dried in vacuo overnight affording 32.55 g of 22,23-dihydro avermectin Bla with a m.p. of 155°-157° C.