Table 3. Substrate scope in the synthesis of β-alkynyl esters (acceptor alkynes) ^a .

^aReaction conditions: (i) 6a : 7b–e ratio = 1.25 : 1.0, 3 mol% Pd(OAc)₂/TDMPP, 1.0 M in PhMe at 23 °C for 1–18 h. (ii) 5 mol% Cu(OAc)₂·H₂O/17, (EtO)₂MeSiH (2 equiv.), t-BuOH (2 equiv.), 0.20 M in PhMe at 4 °C for 14–20 h. Yields are of isolated products after chromatography. Enantiomeric excesses were determined by chiral HPLC analysis.

^bThe reaction reached 80% conversion (¹H NMR) and produced a mixture of 1,4- and 1,6-reduction products (4 : 1 1,4 : Σ1,6, ¹H NMR analysis of the crude reaction mixture), from which pure 9ad was isolated in 54% isolated yield.