Tandem Michael/Michael reactions mediated by phosphines or aryl thiolates (vol 63, pg 1100, 2007)

tri-n-Butyl phosphine was found to effect tandem Michael/Michael cyclisations leading to the formation of cyclopentenes and cyclohexenes in good yields, whilst p-TolSH in conjunction with a catalytic amount of p-TolSNa effected cyclisation to the corresponding cyclopentanes and cyclohexanes.