TY - JOUR
T1 - Palladium-Catalyzed alpha-Arylation of Tetramic Acids
AU - Storgaard, Morten
AU - Dorwald, F. Z.
AU - Peschke, B.
AU - Tanner, David Ackland
PY - 2009
Y1 - 2009
N2 - A mild, racemization-free, palladium-Catalyzed alpha-arylation of tetramic acids (2,4-pyrrolidinediones) has been developed. Various amino acid-derived tetramic acids were cleanly arylated by treatment with 2 mol % of Pd(OAc)(2), 4 mol % of a sterically demanding biaryl phosphine, 2.3 equiv of K2CO3 or K3PO4, and aryl chlorides, bromides, or triflates in THF. With conventional heating, conversions >95% could be attained after 1 h at 80 degrees C, whereas microwave-induced heating led to much shorter reaction times (5 min at 110 degrees C). The electron density of the aryl electrophile had no effect on their reactivity: both electron-rich and electron-poor aryl chlorides and bromides or triflates led to good yields. Ortho-substituted aryl halides and heteroaryl halides, however, did not undergo the title reaction.
AB - A mild, racemization-free, palladium-Catalyzed alpha-arylation of tetramic acids (2,4-pyrrolidinediones) has been developed. Various amino acid-derived tetramic acids were cleanly arylated by treatment with 2 mol % of Pd(OAc)(2), 4 mol % of a sterically demanding biaryl phosphine, 2.3 equiv of K2CO3 or K3PO4, and aryl chlorides, bromides, or triflates in THF. With conventional heating, conversions >95% could be attained after 1 h at 80 degrees C, whereas microwave-induced heating led to much shorter reaction times (5 min at 110 degrees C). The electron density of the aryl electrophile had no effect on their reactivity: both electron-rich and electron-poor aryl chlorides and bromides or triflates led to good yields. Ortho-substituted aryl halides and heteroaryl halides, however, did not undergo the title reaction.
U2 - 10.1021/jo900799y
DO - 10.1021/jo900799y
M3 - Journal article
C2 - 19472991
SN - 0022-3263
VL - 74
SP - 5032
EP - 5040
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
IS - 14
ER -