Tris rhodium chloride ketones

The reduction of keto steroids by treatment with chloroiridic acid, or sodium chloroiridate, and trimethyl phosphite has been studied in some detail.Ketones at the 2- and 3-positions are reduced predominantly to the corresponding axial alcohols, while ketones at 4,6,7,11,12,17 and 20 are not affected. The rate of reaction is increased by addition of aqueous sodium hydroxide. Replacement of sodium chloroiridate by tris(triphenylphos-phine)rhodium chloride gives a system which reduces a 3-keto steroid to the... 

Enones are reduced to saturated ketones by catalytic hydrogenation provided the reaction is stopped following the absorption of 1 mol of hydrogen. " A number of catalysts were found useful for this, including platinum, platinum oxide,Pt/C, " Pd/C, - Rh/C, " tris(triphenylphosphine)rhodium chloride, - nickel-aluminum alloy in 10% aqueous NaOH, and zinc-reduced nickel in an aqueous medium. Mesityl oxide is formed from acetone and reduced in a single pot to methyl isobutyl ketone using a bifunctional catalyst which comprised palladium and zirconium phosphate (Scheme 20). 

A neat mixture of the /l-unsaturated ketone (10mmol), triethylsilane (11 mmol), and tris(triphenylphosphine)rhodium(i) chloride (0.01 mmol) was stirred at 50°C for 2h, and the product silyl enol ether was distilled directly (yields 90-98%). 

Decarbonylation of a /9-aldehyde 3 has been achieved at elevated temperatures using a catalytic amount of tris(triphenylphosphane)rhodium(I) chloride (Wilkinson s catalyst) and of a 1 -cy-clopropylalkyl phenyl ketone using potassium tert-butoxide. ... 

Addition (See also Michael reaction. Thiele reaction.) Acrolein. Cuprous chloride. Cuprous iodide. Diethylaluminum cyanide. Difluoramine. Dimethylcopper lithium. Methyl(tri-K-butylphosphine)copper complex. Methyl vinyl ketone. Rhodium trichloride. Sulfur dichloride. 

Example of use with dimethylphenylsilane (11). A mixture of the a/3-unsaturated ketone (1.05 mmol), dimethylphenylsilane (1.1 mmol) and tris(triphenylphosphine)rhodium(i) chloride (0.002 mmol) was heated at 55 °C for 1 h. The silyl enol ether was distilled directly from the reaction. 

Several syntheses are available to the 13,14-dihydroprostaglandins, some of which are metabolites of the E and F series. The first of these routes [143, 144] started from the formyl derivative (LVII) of the enol ether of cyclo-pentan-l,3-dione which on reaction with ethyl 6-bromosorbate and tri-phenylphosphine followed by selective catalytic reduction afforded the ester (LVIII). A second formylation followed by elaboration with n-hexanoyl-methylenetriphenylphosphonium chloride 1 to the ketone (LIX) which on reduction of the exocyclic double bond and acid-catalysed solvolysis in benzyl alcohol afforded the benzyl ether (LX) and its isomeric enol ether. Reduction with lithium tri-t-butoxyaluminium hydride to the corresponding 15-hydroxy-compound and palladium-charcoal catalysed hydrogenolysis followed by prolonged catalytic hydrogenation with rhodium-charcoal led to ( )-dihydro-PGEi ethyl ester. 

The synthesis of highly substituted /Sy-unsaturated ketones has been accomplished by reaction of allylmagnesium halides with 4,4-dimethyl-2-oxazolines. In the presence of a catalytic amount of chlorotris(triphenylphosphine)-rhodium(l), acyl chlorides and allyl tri-n-butyltin give the corresponding alkyl allyl ketone. A simple regiospecific synthesis of allyl ketones from allyl alcohols (Scheme 62) has been reported. ... 

Ketosteroids are selectively converted to their dimethylketals by tris-(tri phenyl phosphine) rhodium (I) chloride ond CH30H. Ketonic groups elsewhere in the steroid system are unchanged. 

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