1354655-30-3Relevant articles and documents
Phospha-Michael additions to activated internal alkenes: Steric and electronic effects
Lenker, Heather K.,Richard, Marcia E.,Reese, Kyle P.,Carter, Anthony F.,Zawisky, Jason D.,Winter, Eric F.,Bergeron, Timothy W.,Guydon, Krysta S.,Stockland, Robert A.
experimental part, p. 1378 - 1385 (2012/03/11)
The addition of P(O)-H bonds to internal alkenes has been accomplished under solvent-free conditions without the addition of a catalyst or radical initiator. Using a prototypical secondary phosphine oxide, a range of substrates including cinnamates, crotonates, coumarins, sulfones, and chalcones were successfully functionalized. Highly activated acceptors such as isopropylidenemalononitrile and ethyl 2-cyano-3-methyl-2-butenoate underwent the phospha-Michael reaction upon simple trituration of the reagents at room temperature, whereas less activated substrates such as ethyl cinnamate and methyl crotonate required heating (>150 °C) in a microwave reactor to achieve significant consumption of the starting alkenes. For the latter alkenes, a competing reaction involving disproportionation of the ditolylphosphine oxide into ditolylphosphinic acid and ditolylphosphine was observed at the high temperatures needed to promote the addition reaction.
