Enantioselective Steglich Rearrangement of Oxindole Derivatives by Easily Accessible Chiral <i>N</i>,<i>N</i>-4-(Dimethylamino)pyridine Derivatives
作者:Hiroki Mandai、Takuma Fujiwara、Katsuaki Noda、Kazuki Fujii、Koichi Mitsudo、Toshinobu Korenaga、Seiji Suga
DOI:10.1021/acs.orglett.5b02089
日期:2015.9.18
Chiral N,N-4-(dimethylamino)pyridine (DMAP) derivatives, which can be readily prepared by the Ugi multicomponent reaction in a one-pot manner, have been efficiently applied to the enantioselective Steglich rearrangement of oxindole derivatives to give the desired products bearing a quaternary carbon center in high yield (>98% yield) and with high enantioselectivity (up to 99:1 er).
Development of Chiral Nucleophilic Pyridine Catalysts: Applications in Asymmetric Quaternary Carbon Synthesis
作者:Scott A. Shaw、Pedro Aleman、Edwin Vedejs
DOI:10.1021/ja037223k
日期:2003.11.1
TADMAP (1a), a new chiral DMAP catalyst, has been designed to place a C(3)-benzylic trityl group over one face of the pyridine ring, while a C(3)-benzylic acetoxy group creates a chirotopic environment on the other face. TADMAP was prepared in four steps (37% overall) from triphenylacetic acid and (dimethylamino)pyridine and was resolved using camphorsulfonic acid. TADMAP catalyzes the enantioselective rearrangement from oxazolyl phenyl carbonates 4 to azlactones 5, from furanyl phenyl carbonate 8 to the furanone 9, from the benzofuranyl carbonates 11a and 11b to benzofuranones 12a and 12b, and from the indolyl carbonates 11c and 11d to oxindoles 12c and 12d. The products are formed in good yield and, in most cases, with practical levels of enantiomer excess at the newly formed quaternary carbon.
[EN] PYRIDINE DERIVATIVE HAVING AXIAL CHIRALITY OR SALT THEREOF, AND ASYMMETRIC CATALYST COMPRISING SAME<br/>[FR] DÉRIVÉ DE PYRIDINE AYANT UNE CHIRALITÉ AXIALE OU SEL DE CELUI-CI, ET CATALYSEUR ASYMÉTRIQUE LE COMPRENANT<br/>[JA] 軸不斉を有するピリジン誘導体又はその塩、及びそれからなる不斉触媒
Enantioselective TADMAP-Catalyzed Carboxyl Migration Reactions for the Synthesis of Stereogenic Quaternary Carbon
作者:Scott A. Shaw、Pedro Aleman、Justin Christy、Jeff W. Kampf、Porino Va、Edwin Vedejs
DOI:10.1021/ja056150x
日期:2006.1.1
efficient and are used to prepare chiral lactams (23) and lactones (30) containing a quaternary asymmetric carbon. TADMAP-catalyzed carboxyl migrations in the indole series are relatively slow and proceed with inconsistent enantioselectivity. Modeling studies (B3LYP/6-31G*) have been used in qualitative correlations of catalyst conformation, reactivity, and enantioselectivity.
Asymmetricsynthesis: A class of cinchona alkaloid-derived zwitterions has been successfully applied to highly enantioselective Steglich rearrangement of oxindoles. The same catalytic system is also applicable in the asymmetric aldol reaction of oxindoles. This finding paves the way to the development of new reaction protocols exploiting cinchona alkaloid-derived zwitterions as asymmetric nucleophilic