New Spirocyclic Oxindole Synthesis Based on a Hetero Claisen Rearrangement

Abstract

[reaction: see text] A new method for preparing spirocyclic oxindoles is presented. Featuring a [3,3]-sigmatropic enolate rearrangement, the three-step process converts carboxylic acid starting materials to oxidnole products in overall yields of 52-76%. The enolate rearrangement step occurs at -78 degrees C and provides easy access to oxindole products that have previously been difficult to prepare.

A Total Synthesis of (±)-Leuconodines D and E

“…Thus, the structure of the more polar diastereoisomer was determined to be 25 . Next, heating the mixture of 24 and 25 in the presence of NaCN , cleaved cleanly the methoxycarbonyl group and afforded a mixture of diastereoisomer amine 27 and 28 , which could be easily separated by flash column chromatography in 30% and 31% yields over two steps from 23 , respectively. The relative stereochemistries of 27 and 28 could be assigned through a comparison of their spectroscopic information with those of the relative stereochemistries of well-defined diastereoisomers 24 and 25 .…”

(Substituted Ylidene)Amino‐2‐Oxo‐Indolylidene Thioureas and Bis(2‐Oxo‐Indolylidene)Urea from (Ylidene)Thiocarbonohydrazides and Isatylidene Malononitrile

“…Isatin nucleus is probably one of the most widely distributed heterocyclic ring systems found in many alkaloids and drugs as well as dyes . Many synthetic methodologies have been developed for constructing spiro‐cycles containing 2‐oxoindole, most of which based on cycloaddition or condensation reactions .…”

Synthesis and Reaction of Novel Spiro Pyrimidine Derivatives

“…As a result to that, most of synthetic methodologies have been developed for constructing these spiro cycles, most of which were based on cycloaddition or condensation reactions . In this report, we have been and continue to discuss the development of new and simple synthetic methods for the efficient preparation of spiro heterocycles containing pyrimidine ring.…”