ABSTRACT
We report a highly enantioselective Morita-Baylis-Hillman (MBH) reaction of isatins and acrolein to provide enantiomerically enriched 3-substituted 3-hydroxyoxindoles, which could serve as valuable synthetic building blocks. This is also the first time that a ketone has been used as the electrophile and acrolein as the nucleophile in a highly enantioselective catalytic asymmetric MBH reaction. Hatakeyama's catalyst, ß-isocupreidine (1), turned out to be a powerful catalyst for this transformation.
ABSTRACT
Quinidine derivative (QD)(2)PYR was found to catalyze the asymmetric direct amination of unprotected prochiral 3-oxindole with DIAD to construct quaternary stereocenters at the C3 position with excellent enantioselectivity.
Subject(s)
Amines/chemistry , Indoles/chemistry , Amination , Catalysis , Oxindoles , StereoisomerismABSTRACT
Tillering is one of the most important agronomic traits of rice. In order to explore the molecular mechanism of rice tillering, a high-tillering dwarf 1-2 (htd1-2) mutant was isolated from the offspring of the indica rice (Oryza sativa L. ssp. indica) variety 9311 treated with 350Gy 60Co gamma-radiation. Genetic analysis showed that both high tillering and dwarf phenotypes of htd1-2 were controlled by a single recessive nuclear gene. By means of molecular marker technique, the HIGH-TILLERING DWARF1-2(HTD1-2) gene was mapped between two CAPS markers A6 and E2 on chromosome 4 within 116 kilobases. Within this region, there is a cloned gene HIGH-TILLERING DWARF1(HTD1), which controls rice tillering. By comparing sequences of HTD1 between htd1-2 and 9311, in combination with the results from dCAPS analysis, we believed that HTD1 is an orthologue of the gene HTD1-2. Because of different genetic backgrounds, htd1 and htd1-2 have different phenotypes although they are the allelic mutants. Furthermore, removal of axillary buds proved that dwarfism of htd1-2 mutant is partly attributed to its excessive tillers.
