Phosphine-mediated Additions Of ?,?-unsaturated Ketone

Phosphines have been widely used in synthetic chemistry.Due to the high nucleophilic reactivity of phosphine,it could be used as catalyst in nucleophilic additions,especially in the addition of?,?-unsaturated carbonyl compounds.On the other hand,phosphine could be applied as stoichiometric reagents in some named reactions,which have significance in organic synthesis,including Wittig reaction,Staudinger reaction and Mitsunobu reaction.This thesis describes the addition of?,?-unsaturated ketones.Activated alkenes,allenes,alkynes and MBH alcohol derivatives are common electrophiles in phosphine-catalyzed nucleophilic additions.Among them,activated alkynes are mainly used as C3 synthon in asymmetric[3+2]annulations.However,the asymmetric[4+1]annulations in which the activated alkynes are applied as C1synthon are rarely reported.The first work employed the bifunctional bisphosphine to catalyze the[4+1]annulations of terminal ynones and tryptamine-derived oxindoles.The spiro-oxindoles were obtained with high yields?up to 92%?,excellent enantioselectivities?up to 97%ee?and good diastereoselectivities?>20:1?.In the second work,the Staudinger reduction of azides was explored based on the reduction ability of phosphines.The hydroaminations of?,?-unsaturated ketones were realized?up to 96%yield?via the Staudinger reaction/aza-Michael addition of azides and?,?-unsaturated ketones.The ³¹P NMR experiments demonstrated that the Staudinger reaction of azides is the initial procedure of this reaction.The phosphine-catalyzed reactions of active allene and pronucleophile have been widely investigated.However,the phosphine-catalyzed reaction of terminal ynone and pronucleophile was rarely explored.In the third work,the phosphine-catalyzed asymmetric additions of terminal ynones and 5H-oxazol-4-ones have been preliminarily explored.The addition products were attainable with moderate yields,good regioselectivities and enantioselectivities,but several substrates couldn't be suitable for this reaction.