“…Tetrahydrofuran was distilled from sodium benzophenone ketyl and pyridine was distilled from calcium hydride. The following were prepared according to published procedures: 3-Methoxybut-1-yne (1i), [27] 4-(trimethylsilyloxy)pent-1-yne (1j), [28] 4-(tert-butyldimethylsilyloxy)pent-1-yne (1k), [29] 5-[tert-butyl(dimethyl)silyloxy]pent-1-yne (1l), [30] 4-pentynyl benzyl sulfide (1m), [26b] diethyl 6-bromo-6-hepten-1-yne-4,4-dicarboxylate (1o), [31] 6-cyclopropylidenehex-1-yne (1p), [32] 1-(trimethylsilyl)hepta-1,6-diyne (1q), [32] 2-[(E)-ethoxy]-1-ethynylcyclopropane (1y), [33] 1-hexen-5-yne (1z), [33] hexylphenylethyne (1he), [34] cyclopropylphenylethyne (1hc), [34] ethyl p-phenylethynylbenzoate (1hh 1 ), [35] methyl 4-(4-methoxyphenylethynyl)benzoate (1h 2 h 3 ), [35] bis(p-trifluoromethylphenyl)ethyne (1h 4 h 4 ), [35] 1,4-bis(p-trifluoromethylphenyl)-1,3-butadiyne (1h 4 z), [36] 1,4-bis(pmethoxyphenyl)-1,3-butadiyne (1h 3 z 2 ), [36] (2S)-methoxymethyl-pyrrolidine (2e), [37] methyl (2S)-pyrrolidinecarboxylate (2f), [38] diethyl (2S)-NЈ,NЈ-diethylpyrrolidinecarboxamide (2g), [39] (2R,5R)-dimethylpyrrolidine (2h), [40] trans-2,3-dimethylaziridine (2i), [41] (1S)-(1-phenyl)ethylmethylamine (2j), [42] pentacarbonyl[(2E)-3-(dimethylamino)-1-ethoxy-3-(trimethylsilyl)-2-propen-1-ylidene]chromium (3ga), [8] pentacarbonyl(1-ethoxy-2-hexyn-1-ylidene)chromium (5, R 1 ϭ nPr) [43] .…”