Ratcliffe reagent

Raney nickel, 135, 312,411 Ratcliffe reagent, 37, 70 Redudion decyanization, 324-325 Reductive dimerization, 369 Reformatsky-type reactions, 151-152 Resolution, 79,113 Resorcinol dibenzoate, 57 Retinal, 372 Retroaldol reaction, 303 RhodiumGl) acetate, 76, 313 Rhodium(II) n-butanoate, 313 Rhodium(II) carboxylates, 313 Rhodium(III) chloride, 313-314 Rhodium(III) chloride-Triphenylphosphine, 314... 

Allylic oxidation (3, 35). NBS is somewhat superior to the Ratcliffe reagent (CrO , Py, 4, 96) for oxidation of (1) to a- and )3-levantenolide, (2) and (3), dllerpenes of the Nicotiana species. The reaction was carried out in dioxane-wuter in the presence of calcium carbonate. An intermediate furanc may account for the formation of the anomalous 8-isomer (3). ... 

The Ratcliffe Reagent is prepared in situ in dichloromethane. Largely replaced by PCC and PDC. 

Cr03-pyridine complex (Sarett reagent), 1, 145-146 2, 74-75. Ratcliffe and Rodehorst4 find that the reagent can be prepared in situ directly in methylene chloride. Chromium trioxide (60 mmol.) is added to a stirred solution of pyridine (120 mmol.) in methylene chloride. The deep burgundy solution is stirred for 15 minutes at room temperature and then a solution of the alcohol (10 mmol.) in methylene chloride is added. A black deposit separates, and the product is isolated from the filtrate. One main advantage is that the complex can be prepared safely in this way without fire hazard. 

CrOa -pyridine complex, Ratcliffe s reagent (4, 96) can be used for allylic oxidations without isolation of the crystalline complex if all reagents are kept completely dry. ... 

Sulfenylation of C-7 imino carbanions was also exploited by Spitzer and Goodson (1973) in preparing 7a-methylthioamides 354-357, and by Ratcliffe and Christensen (1973) in their synthesis of cefoxitin. The former workers used lithium diisopropylamide in DMF (-78°C) to generate the Schiff base anion. Methylthiolation was performed with excess methoxy-carbonylmethyl disulfide. Liberation of the modified nucleus was achieved with Girard-T reagent in aqueous DMF. This series of methylthioamides was subsequently transformed with chlorine to the corresponding 7a-methoxyamides, presumably via the intermediacy of acylimines. 

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