Intramolecular Cycloaddition Azomethine Ylides and α‐(Trifluoromethyl)styrenes as Dipolarophiles

Abstract

The synthesis of polycyclic fluorinated tertiary amines has been accomplished by means of an intramolecular azomethine ylide cycloaddition with fluorinated dipolarophiles. Thus, tri‐ and tetracyclic fused pyrrolidines bearing a quaternary trifluoromethyl group were obtained in moderated yields in a stereoselective manner. This is one of the few examples reported in the literature of intramolecular 1,3‐dipolar cycloaddition of azomethine ylides with fluorinated dipolarophiles. Initial attempts of the asymmetric version of the process have been performed, but low levels of diastereoselectivity were achieved.

Fluoroalkyl N-sulfonyl hydrazones: An efficient reagent for the synthesis of fluoroalkylated compounds

“…pyrrolidines [52]. According to the proposed mechanism, the base-promoted decomposition of N-tosyl hydrazones results in diazo compounds 16-1, which then react with preformed aryl palladium complex 16-2 (formed from the aryl bromide The migratory insertion then occurs, yielding alkyl palladium complex 16-4.…”

The Crucial Role of S‐oxidation State on the Selectivity and Reaction Rate of the 1,3‐Dipolar Cycloaddition of Azomethine Ylides and Homochiral Thiazolines

“…[1,2] A vast number of publications have been published since several years ago dealing with the insights of this cycloaddition due to the versatile organic molecules obtained through this methodology. [3][4][5][6][7][8][9][10][11][12] More interesting is the asymmetric version of this reaction, which allows to obtain up to 4 stereogenic centers in one reaction step in a selective manner, classically achieved by the use of metal-or organocatalysis. [13][14][15][16][17][18][19][20][21] The origin of the exo/endo selectivity in the catalytic asymmetric synthesis of pyrrolidines by 1,3-dipolar cycloaddition of azomethine ylides has been brilliantly rationalized and reported recently.…”

(3 + 2) Cycloaddition Reaction of the Endocyclic N-Silyl Enamine and N,N′-Cyclic Azomethine Imine

“…This reaction can demonstrate the versatility of the N -silyl enamine intermediates for the synthesis of the complex organic molecules. Moreover, the resulting tetracyclic pyrazolidinone skeleton has an unprecedented structure with consecutive three stereocenters. − …”