Scheme 2. Scope of electron-withdrawing group and allyl alcohols. Major diastereomer depicted in all cases. Diastereomeric ratio (d.r.) determined from the crude ¹H NMR spectrum and reported to the nearest whole number. a = 1 h PBu₃ (5 mol%) catalysed conjugate addition, 1 h irradiation; b = 1 h PBu₃ (15 mol%) catalysed conjugate addition, 1 h irradiation; c = 1 h PMe₃ (20 mol%) catalysed conjugate addition, 1 h irradiation; d = 1 h PMe₃ (20 mol%) catalysed conjugate addition, 16 h irradiation; *63% ¹H NMR yield and 26% isolated yield after recrystallisation.