An organocatalyticenantioselective Michael–Michael cascadereaction is developed for the synthesis of chiral spirotetrahydrothiopyrans. This highly functionalized scaffold was assembled in moderate to good yield (55–74%) and excellent diastereo- and enantioselectivities (>30:1 dr, ≥ 99% ee) with the creation of fourconsecutive stereogenic centers. The novel spiro-oxindole scaffold is validated as
Time-Economical Synthesis of Bis-Spiro Cyclopropanes via Cascade 1,6-Conjugate Addition/Dearomatization Reaction of <i>para</i>
-Quinone Methides with 3-Chlorooxindoles
A simple method involving DBN‐mediated spirocyclopropanation of para‐quinonemethides with 3‐chlorooxindoles is reported, providing a novel class of bis‐spiro compounds in short reaction times under mild conditions. Twenty‐four examples of the target compounds were obtained in up to 96 % yield.
DABCO-Catalyzed Michael/Alkylation Cascade Reactions Involving α-Substituted Ammonium Ylides for the Construction of Spirocyclopropyl Oxindoles: Access to the Powerful Chemical Leads against HIV-1
作者:Lin Chen、Jin He
DOI:10.1021/acs.joc.9b03164
日期:2020.4.17
tactic has been highlighted by a gram-scale reaction and Suzuki cross-coupling reactions of the product. Moreover, the reaction mechanism has been tentatively elucidated by control experiments and dynamic high-resolution mass spectrometry studies, which indicates that the Michael/alkylation cascade reaction involves DABCO-derived α-substituted ammoniumylides.
Asymmetric synthesis of 3-spirocyclopropyl-2-oxindoles via intramolecular trapping of chiral aza-ortho-xylylene
作者:Xiaowei Dou、Weijun Yao、Bo Zhou、Yixin Lu
DOI:10.1039/c3cc45369c
日期:——
Chiral aza-ortho-xylylene intermediates were efficiently generated from 3-chloro-3-substituted oxindole precursors. The first intramoleculartrapping of chiral aza-ortho-xylylene intermediates led to a highly asymmetric synthesis of 3-spirocyclopropyl-2-oxindoles.