Mono-aryl internal alkynes

It is important to note that both aliphatic and aromatic vinyl ketones were viable substrates in which P-alkyl and P-aryl substitutions were tolerated. Diaryl alkynes, mono-aryl internal alkynes, nonaromatic internal alkynes, terminal alkynes, and free hydroxyl-bearing alkynes were all efficient participants. It should be mentioned that while ynoates were successful nucleophiles, enoate electrophiles were found to be poor participants in nickelotalyzed couplings. 

Reductive cycHzations have been shown to be diastereoselective in the synthesis of bicyclic products as well as various macrocycles. There are also instances of chirahty transfer in intermolecular reductive couphngs. The synthesis of anti-1,2-diols has been demonstrated using a-alkoxyaldehydes with a methoxymethyl ether (MOM) protecting group and mono-aryl internal alkynes (Scheme 8.25) [49]. Dias-tereoselectivities are high for the formation of anfi-l,2-diols in cases where the aldehyde has a branched sp -P-carbon. 

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