Change in the selectivity of the action of catalysts in the hydrogenation of the dienone group

Remarkably Selective Reduction of the α,β-Carbon−Carbon Double Bond in Highly Activated α,β,γ,δ-Unsaturated Alkenes by the InCl3−NaBH4 Reagent System

“…The Birch reduction with lithium and ammonia of an α,β,γ,δ-unsaturated steroidal ketone produces a β,γ-unsaturated ketone . In another report, hydrogenation with Ni−Al 2 O 3 under very controlled conditions reduces the γ,δ-unsaturated double bond while the presence of Pb or Cd reduces the α,β-one . The reduction of the α,β-double bond is also observed using triallylsilane in the presence of either rhodium 3 or platinum 4 catalyst.…”

“…1 In another report, hydrogenation with Ni-Al 2 O 3 under very controlled conditions reduces the γ,δ-unsaturated double bond while the presence of Pb or Cd reduces the R,β-one. 2 The reduction of the R,βdouble bond is also observed using triallylsilane in the presence of either rhodium 3 or platinum 4 catalyst. The reduction of R,β,γ,δ-unsaturated carboxylic ester by trialkylsilane in the presence of Wilkinson's catalyst provides β,γ-unsaturated ester from acyclic molecules, whereas in cyclic strained compounds the R,β-double bond is reduced.…”

“…The reduction of α,β,γ,δ-unsaturated carbonyl compounds is very complicated because of the presence of three reducible positions. A literature survey shows a few isolated examples, − and no general study was found. The Birch reduction with lithium and ammonia of an α,β,γ,δ-unsaturated steroidal ketone produces a β,γ-unsaturated ketone .…”