Raney-Ni

Scheme 12 Total synthesis of (-)-xestospongin A (116), (+)-araguspongine B (129), and (+)-xestospongin C (130) [41]. Experimental conditions i. (a) NaH, THE, (b) -BuLi, (c) 132 a. Ru(II)-S-BINAP, H2, EtOH Hi. LiBH4, Et20 iv. PPTS, 2,2-dimethoxypropane, acetone v. Nal, acetone, reflux vi. 3-picoline, EDA, THE vii. HCl(aq.), EtOH viii. TsCl, EtsN, CH2CI2 ix. Nal, butanone, reflux x. LiBH4, MeOH, i-PrOH xi. DEAD, CH2CI2 xii. H2, Ni (Raney), MeOH xiii. Rh on alumina, MeOH, H2, then add alumina, reflux...

Scheme 27. i, Ij, THF ii, P(OEt)j rfx iii, t-BuMejSiCl, imidazole, DMF iv, CF3COOH-H2O v, AcjO-DMSO vi, NHjOH, MeOH-THG vii, Hj, Ni-Raney viii, ACjO-dimethylaminopyridine-CHjClj ix. B2H6-THF X, MejSil... 

Raney Nickel [Raney Ni, Raney nickel catalyst or Raney s nickel catalyst (Refs 1, 2 2a)j. 

Scheme 12.23. Synthesis of burseran using a three-component conjugate addition/Wacker-type cyclization, by Balme and co-workers [79]. DMSO = dimethylsulfoxide, THF = tetrahydrofuran, Ra-Ni = Raney nickel.

Polyisobutylene Cyclohexane Reduction with H2/Ni Raney a, U-Macrodiols [134]... 

Polybutene Suspension in hexane Thermal decomposition of peroxides and reduction with Ni Raney or LiAlH4 Polyols [137, 138]... 

Dichlorophenyl)-l-piperazinopropionitrile (20.0 g), acetic anhydride (100 ml), anhydrous sodium sulfate (12.0 g) and a 50% solution of Ni-Raney (6 ml) are hydrogenated at 60.0 pounds per inch at 60°C in a Parr apparatus. After about half an absorption of hydrogen is complete. The reaction mixture is cooled, the is filtered and the solution is concentrated to small volume in a rotating evaporator. The residue is treated with NaOH solution and extracted several times CH2CI2. The organic layer is washed, dried and evaporated. The residue is crystallized from ethyl acetate. 14.0 g of the l-(3-acetylaminopropyl)-4-(2,5-dichlorophenyl)piperazine are obtained, melting point 114°C. 

D-Glucose was reduced to the D-sorbitol with a hydrogen over Ni Raney, then it was turned into the L-sorbose with the acetobacter suboxydans and the hydroxyl groups of L-sorbose were protected with acetone treatment yielded the diaceton-L-sorbose. Subsequent treatment with NaOCI/Raney Ni produced di-O-isopropylidene-2-oxo-L-gulonic acid. Partial hydrolysis with aqueous HCI gave deprotected 2-oxo-L-gulonic acid, which yielded ascorbinic acid by heating with HCI. 

A regio- and stereoselective [2+2] cycloaddition between cyclohexadiene acetonide 143 and ketene 144 afforded compound 142. The required ary-lamine unit was introduced by means of the orfho-mclallalcd aniline equivalent 145, after the failure of many other aryl metal species to give the desired transformation. The triazene unit in compound 146 thus obtained was chemoselectively reduced to the corresponding amine by Ni Raney, and this... 

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