Addition of alkynes to aldehydes and activated ketones catalyzed by rhodium-phosphine complexes.

A mixture of 2-(di-tert-butylphosphino)biphenyl and dicarbonylacetonato rhodium(I) provides an effective catalyst system for the addition of alkynes to aldehydes and activated ketones. In contrast to the more common zinc-catalyzed processes, enolizable 1,2-dicarbonyls are excellent substrates for these rhodium-catalyzed additions. This reaction allows for the formation of propargylic alcohols under mild conditions, tolerating many functional groups (such as carboxylic acids) that are incompatible with other methods.

Rhodium-catalyzed addition of alkynes to activated ketones and aldehydes.

[reaction: see text] The rhodium-catalyzed addition of alkynes to 1,2-diketones, 1,2-ketoesters, and aldehydes provides a method for the synthesis of tertiary alkynyl alcohols under mild conditions. The reaction tolerates many functional groups (such as carboxylic acids) that are incompatible with other methods. The alkyne addition reaction proceeds best using bulky phosphine ligands such as 2-(di-tert-butylphosphino)biphenyl.