Visible Light Promoted Alkylation,Acylmethylation Of Baylis-Hillman Acetates And Sulfinylation/Cyclization Of Enamidones

Baylis-Hillman acetate are readily available fundamental feedstock in the field of organic synthesis,Although a large number of reactions to construct C-S,C-X,C-N,C-P,C-O,and C-C bonds from Baylis-Hillman acetate have been widely studied by chemists in this field,these transformations suffer from expensive transitionmetals,limitation of the substrate scope,and lower yields.Therefore,it is important to develop simpler,green and efficient synthesis methods.As an important supplement to traditional methods,visible photocatalysis has the advantages of environmental protection,cheapness and sustainability.Thus,the research contents are as follows:（1）A visible-light-promoted decarboxylative alkylation of Baylis-Hillman acetates with N-（acyloxy）phthalimides to access trisubstituted alkyl acrylates under metal-free reaction conditions was developed.The reaction show better stereoselectivity of the E confifiguration,a total of 29 substrates were expanded,and yield up to 98%.N-（acyloxy）phthalimides derived from primary,secondary and tertiary alkyl carboxylic acids can react smoothly.This work offers an economic and easily handled approach to C（sp²）-C（sp²）and C（sp³）-C（sp³）bond fomation in one step.Moreover,this protocol could be applied to the late-stage functionalization of natural products.（2）The visible-light-promoted acylmethylation of Baylis-Hillman acetate usingα-bromoacetophenone as acylmethylation reagent to synthesize 1,5-dicarbonyl derivatives.Acylmethylation products were obtained under the catalytic system of Rose Bengal/TIPA.However,in the catalytic system of Ir（ppy）₃/K₂HPO₄,the bromoacylmethylation reaction was realized,which can efficiently construct C-Br bonds and C-C bonds at the same time,yield up to 98%.This method shows broad substrate scope,and good functional group tolerance.（3）A highly efficient and eco-friendly method for the tetramethylammonium iodide-mediated sulfenylation/annulation of enaminones using thiosulfonates as the sulfenyl source was described under metal-and oxidantfree conditions.The reaction proceeds smoothly under air,which provides a new idea for the construction of C-S bonds.