Enantioselective Michael/Cyclization Reaction Sequence: Scaffold‐Inspired Synthesis of Spirooxindoles with Multiple Stereocenters

Abstract

In‐spir‐ierend: Mit 1 als Katalysator konnte erstmals die Titelreaktion von α‐Isothiocyanatoimiden mit Methylenindolinonen realisiert werden. Diese Synthesemethode bietet einen einfachen, effizienten, umweltschonenden und enantioselektiven Zugang zu hochfunktionalisierten Spirooxindolen mit drei aufeinander folgenden Stereozentren.

Molecular diversity of spirooxindoles. Synthesis and biological activity

“…Bifunctional catalysts 221 [126] 10 mol % [129] 10 mol % [122] 15 mol % [127] 15 mol % [123] 15 mo l% [128] 15 mol % Scheme 59 Construction of spirooxindoles through an organocatalytic cascade Michael-cyclization sequence [141][142][143]145]. A plausible mechanism for this process may probably involve the formation of arylidenemalononitriles A via Knoevenagel condensation reaction of isatins methylene active nitriles 240 using various bases.…”

Highly Enantioselective Organocatalytic Michael Addition/Cyclization Cascade Reaction of Ylideneoxindoles with Isothiocyanato Oxindoles: A Formal [3+2] Cycloaddition Approach to Optically Active Bispirooxindole Derivatives

“…As shown in Scheme , treatment of 3aa with CH 3 I under basic conditions gave product 4 6f,8 in 91 % yield with >99 % ee and >95:5 dr . Furthermore, the oxidation of bispirooxindole 3aa with 30 % aqueous H 2 O 2 and 98 % formic acid efficiently generated corresponding lactam 5 (99 % yield, >99 % ee , >95:5 dr ) 6g,6h,8. Note that no loss of the diastereo‐ or enantioselectivity was observed.…”

Catalytic Asymmetric 1,2‐Addition of α‐Isothiocyanato Phosphonates: Synthesis of Chiral β‐Hydroxy‐ or β‐Amino‐Substituted α‐Amino Phosphonic Acid Derivatives

“…Catalytic asymmetric transformations employing α‐isothiocyanato compounds have recently been found to be very useful processes for the enantioselective construction of a variety of useful chiral compounds 12. As part of our ongoing interest in transformations involving α‐isothiocyanato compounds12i,j,n,o,q,r and the asymmetric synthesis of amino phosphonic acid derivatives,13 we focused our attention on the development of a novel synthetic method involving the use of isothiocyanato compounds for the construction of functionalized chiral α‐amino phosphonic acid derivatives. The poor nucleophilicity of anionic α‐amino phosphonic acid equivalents results in a small equilibrium constant for their addition to electrophiles.…”