P(PhCH(2)NCH(2)CH(2))(3)N: an efficient lewis base catalyst for the synthesis of propargylic alcohols and Morita-Baylis-Hillman adducts via aldehyde alkynylation.
Proazaphosphatrane P(PhCH(2)NCH(2)CH(2))(3)N (1a) is an efficient catalyst for the addition of aryl trimethylsilyl alkynes to a variety of aromatic, aliphatic, and heterocyclic aldehydes in THF at room temperature. The reaction conditions are mild and employ a low catalyst loading (ca. 5 mol %). Only propargylic alcohols were isolated in good to excellent isolated yields when electron-rich, electron-neutral, heterocyclic, and aliphatic aldehydes were employed, whereas beta-branched Morita-Baylis-Hillman (MBH) type adducts were isolated with electron-deficient aromatic aldehydes after conventional acid hydrolysis of the TMS ether products. Alkynes containing heterocyclic and aromatic groups bearing electron-withdrawing or -donating substituents underwent clean addition to cyclohexanecarboxaldehyde and to electron-rich aromatic aldehydes to give propargylic alcohols in excellent isolated yields. beta-Branched Morita-Baylis-Hillman (MBH) type adducts were isolated when electron-deficient aromatic aldehydes were employed. Reaction pathways to both types of products are proposed.
Wadhwa
Kuldeep
K
Department of Chemistry, 1275 Gilman Hall, Iowa State University, Ames, Iowa 50011, USA.
Chintareddy
Venkat Reddy
VR
Verkade
John G
JG
D000438:Alcohols / Q000138:chemical synthesis / Q000737:chemistry; D000447:Aldehydes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D002845:Chromatography / Q000379:methods; D004583:Electrons; D005663:Furans / Q000737:chemistry; D006868:Hydrolysis; D009943:Organophosphorus Compounds / Q000737:chemistry*; D017553:Phosphorus Compounds / Q000737:chemistry
D000438:Alcohols; D000447:Aldehydes; D000480:Alkynes; D005663:Furans; D009943:Organophosphorus Compounds; D017553:Phosphorus Compounds; C018674:tetrahydrofuran; C449943:P(CH(3)NCH(2)CH(2))(3)N