1 research outputs found
Rh(I)-Catalyzed 1,4-Conjugate Addition of Alkenylboronic Acids to a Cyclopentenone Useful for the Synthesis of Prostaglandins
An efficient and <i>trans</i>-diastereoselective RhÂ(I)-catalyzed
1,4-conjugate addition reaction of alkenylboronic acids and a homochiral
(<i>R</i>)-4-silyloxycyclopentenone useful for the synthesis
of derivatives of prostaglandins E and F is described for the first
time. The reaction functions under mild conditions and is particularly
rapid (≤6 h) under low power (50 W) microwave irradiation at
30 °C in MeOH in the presence of a catalytic amount of KOH. Under
these conditions, 3 mol % of [RhClÂ(COD)]<sub>2</sub> is typically
required to produce high yields. The method also functions without
microwave irradiation at 3 °C in the presence of a stoichiometric
amount of KOH. Under these conditions, only 1.5 mol % of [RhClÂ(COD)]<sub>2</sub> is needed, but the reaction is considerably slower. The method
accepts a range of aryl- and alkyl-substituted alkenylboronic acids,
and its utility has been demonstrated by the synthesis of PGF<sub>2α</sub> (dinoprost) and tafluprost