Chiral Naphthyl-C2-Indole as Scaffold for Phosphine Organocatalysis: Application in Asymmetric Formal [4 + 2] Cycloaddition Reactions
作者:Tingting He、Lei Peng、Shan Li、Fangli Hu、Chuandong Xie、Shengli Huang、Shiqi Jia、Wenling Qin、Hailong Yan
DOI:10.1021/acs.orglett.0c02519
日期:2020.9.4
naphthyl-C2-indole bifunctional phosphine organocatalyst in stereoselective formal [4 + 2] cycloadditionreactions were reported. The chiral naphthyl-C2-indole skeleton was introduced to bifunctional phosphine organocatalysis for the first time, and excellent stereocontrol was achieved in two types of formal [4 + 2] cycloadditionreactions. With the optimal catalyst, a series of chiral spirooxindole and hydrodibenzofuran
N-Alkoxymethylation of Secondary Amides, Sulfonamides and Phosphamides Using Dialkoxymethanes in the Presence of Lewis Acids
作者:Witold Danikiewicz、Rafa Szmigielski
DOI:10.1055/s-2003-37116
日期:——
A convenient and efficient one-pot synthesis of N-alkoxymethyl derivatives of secondary amides, sulfonamides and phosphamides in reaction with the appropriate dialkoxymethanes in the presence of a Lewisacid is described. In this method the use of toxic and carcinogenic chloromethyl alkyl ethers was eliminated.
Novel Methodology for the Efficient Synthesis of 3-Aryloxindoles: [1,2]-Phospha-Brook Rearrangement–Palladium-Catalyzed Cross-Coupling Sequence
作者:Masahiro Terada、Azusa Kondoh、Akira Takei
DOI:10.1055/s-0035-1561859
日期:——
A novelmethodology for the efficient synthesis of 3-aryloxindoles from isatin derivatives was developed. The methodology involves the formation of an oxindole having a phosphate moiety at the C-3 position via the [1,2]-phospha-Brook rearrangement under Bronsted base catalysis followed by palladium-catalyzed cross-coupling with aryl boron reagents. The one-pot synthesis of 3-aryloxindoles from isatin
The asymmetricDarzensreaction between phenacyl bromides and N-protected isatins was developed to synthesize potentially bioactive spiro-epoxyoxindoles. The optically active products were obtained in moderate to good yields and enantioselectivities catalyzed by chiral N,N′-dioxide-Co(acac)2 complexes. A retro-aldol process accompanying the ring-closure step was observed in the process. A chiral control
efficient and catalyticasymmetric alkynylation of isatins has been developed using a bifunctional amidophosphine‐urea/AgBF4 complex as the catalyst. By a combination of metal catalysis and organocatalysis, excellent enantioselectivities (up to 99 % ee) and good yields are achieved. A wide range of both terminal alkynes and isatins are tolerated by this new catalyst system, providing access to structurally