Dihydridotetrakis ruthenium

Dihydridotetrakis (triphenylphosphine) ruthenium(II), RuH2 [P(Ph)3]4, exhibits excellent catalytic activity under mild conditions, transferring hydrogen from ethers, decaline, tertiary amines, and alcohols to aldehydes in about 50% yields. Coordination of the... 

Yamauchi et al. completed an ex-chiral pool synthesis of a samin-type lignan, Scheme (38) [102]. The diprotected tetraol 230 was obtained from Z-glutammic acid by a 15 step procedure in 7-8% overall yield [103]. The diprotected tetraol 230 was treated with boron trifluoride diethyl etherate in dichloromethane to give the tetrahydrofuran 231 in 84%-87% yield. After deprotection with tetrabutylammonium fluoride, the resulting diol was oxidized by dihydridotetrakis(triphenylphospine)ruthenium(II) to provide two lactones 232 and 233 in a ratio of 2 1. Lactone 232 was transformed in samin-type lignan 234 by diisobutylaluminium hydride reduction in 70% yield. 

Selective Oxidations. The selective oxidation of 1,4 and 1,5 primary-secondary diols to lactones is a valuable application of this reagent. Few general mild reagents for the chemoselec-tive oxidation to the hydroxy aldehyde are available. The most widely known reagents are Pt and O2, and Dihydridotetrakis-(triphenylphosphine)ruthenium(II) Hydroxy aldehydes, in their lactol form, are then oxidized further to lactones. The use of TPAP is advantageous in that it is commercially available, employs mild catalytic reaction conditions, and reacts with high selectivity in unsymmetrical cases (eq 8). Lactones have also heen formed from primary-tertiary diols. ... 

Cy2H5iC10yP4Pt2 2 CgHg, M Hydroxo-M peroxo-bis[bis(triphenylphos-phine)platinum(II)] perchlorate benzene solvate, 45B, 1387 Cy 2Hg 2P Pu, Dihydridotetrakis(triphenylphosphine)ruthenium(II), 38B, 1053... 

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