Applications of oxazolidinones as chiral auxiliaries in the asymmetric alkylation reaction applied to total synthesis

Abstract

In this review, a number of applications of chiral oxazolidinones in the asymmetric alkylation reaction applied to total synthesis are described.

Kinetic Resolution of Tertiary 2‐Alkoxycarboxamido‐Substituted Allylic Alcohols by Chiral Phosphoric Acid Catalyzed Intramolecular Transesterification

“…Zuschriften afforded oxazolidinone 5a in 80 %y ield with > 25:1 dr without erosion of the purity;t his product could be used as ac hiral auxiliary in asymmetric synthesis. [10] Ther elative configuration of compound 5a was determined by NOE analysis. [13] Further hydrolysis of 5a with aqueous NaOH solution cleanly removed the protecting group,affording free b-amino alcohol 6a in high yield (Scheme 2b).…”

“…Herein, we report the highly efficient kinetic resolution of tertiary 2-alkoxycarboxamido allylic alcohols (a-hydroxy enecarbamates) by utilizing this reaction with ac hiral phosphoric acid catalyst. [9] Ar ange of racemic tertiary 2-alkoxycarboxamido allylic alcohols (including both aryl,alkyl-and alkyl,alkyl-substituted allylic alcohols) were well resolved under the optimized reaction conditions,generating both the transesterification products and the unreacted tertiary alcohols with high enantioselectivities.T he obtained enantioenriched products can be readily converted into useful chiral building blocks,s uch as oxazolidinones [10] and b-amino alcohols, [11] which have wide applications as chiral auxiliaries, chiral ligands,and biologically active molecules.…”

“…Subsequently,avariety of BINOL-and H 8 -BINOL-derived chiral phosphoric acid catalysts were examined (entries 2-7), and the TCYP catalyst (cat A6)turned out to give the best s factor of 26.6 (entry 6). Next, ar ange of solvents were also explored (entries [8][9][10][11], and PhCl was found to be the optimal one,i nw hich the s factor could be further improved to 37.5 (entry 11). Theleaving groups on the carbamate moiety were also investigated, and we observed that replacing the tBu group with either Et and Bn substituents led to af aster reaction, but also ap oorer kinetic resolution (entries 12 and 13).…”

Applications of Mitsunobu Reaction in total synthesis of natural products

“…[4,5] Due to these advantages salient features, Mitsunobu reaction have been broadly utilized as an important step (steps) in the total synthesis of several natural products and many complex organic molecules. [4] In continuation of our interest in the applications of name reactions in the total synthesis of natural products, [5,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] herein, we try to underscore the applications of the Mitsunobu reaction in the total synthesis of naturally occurring compounds, showing diverse biological properties.…”

Stereospecific Palladium‐Catalyzed Acylation of Enantioenriched Alkylcarbastannatranes: A General Alternative to Asymmetric Enolate Reactions

“…[1] However,t he development of ag eneral approach to employ enolates and enolate equivalents in asymmetric reactions has been hindered by multiple complicating factors.F irst, acatalyst or auxiliary must broadly control facial attack on the enolate independent of the enolate carbon skeleton or the functional groups present. [1] However,t he development of ag eneral approach to employ enolates and enolate equivalents in asymmetric reactions has been hindered by multiple complicating factors.F irst, acatalyst or auxiliary must broadly control facial attack on the enolate independent of the enolate carbon skeleton or the functional groups present.…”