Tributyltin hydride-Sodium iodide

Tributyltin hydride, 316 Zinc iodide, 280 From alkyl halides Lithium aluminum hydride-Ceri-um(III) chloride, 159 Palladium catalysts, 230 Sodium cyanoborohydride-Tin(II) chloride, 280 From alkyl sulfonates Lithium triethylborohydride, 153 From thiols... 

Reductive radical elimination (Barton deoxygenation) of the 3, 4 -xanthate derivative of neamine (70) has been used to prepare the key intermediate 71 (compounds 70, 71) for the synthesis of the 3, 4 -dideoxyneamine analog gentamine Cia [52]. In this synthesis, a precursor possessing free hydroxyl groups at positions 3 and 4 was treated with a mixture of carbon disulfide, aqueous sodium hydroxide, and methyl iodide in DMSO to afford compound 70. Subsequent reduction of 70 with tributyltin hydride furnished the olefin 71, which affer cafalyfic hydrogenation and deprofecfion was converted to gentamine Cia. 

Carretero s chiral 2,6-a5-disubstituted piperidin-4-one intermediate (+)-1423," "" used in the previously described synthesis of (+)-lasubine II (e i-1342) (cf Scheme 180), also made an appearance in a synthesis of (+)-lasubine I (e i-1341) (Scheme 187). In this variant, detosylation of 1423 to (—)-1466 was followed by N-alkylation with l-chloro-4-iodobu-tane and halogen exchange of the alkylated product with sodium iodide under Finkelstein conditions to give the iodo product (—)-1467. The free-radical species generated by treating 1467 with tributyltin hydride in the presence of AIBN underwent fairly efficient (69%) diastereoselective cychzation to the ketone (+)-e i-1377, but also produced a small quantity (16%) of the dehalogenated product (—)-1468. The ketone was reduced in... 

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