Previously, we have shown that both Roche's BIPHEP- and Takasago's SEGPHOS-type ligands are exceptional relative to Ph 3 P for dramatically accelerating the reducing capabilities of in situ generated CuH. 7,8 An extensive study was undertaken to determine which mono- and/or bidentate phosphine ligands would impact the catalytic cycle such that TES ethers could readily be formed from ketones. Figure 1 shows several of the latter, which at S/L ratios of 200:1 ...