K. Rajagopalan

Base catalysed rearrangement of a spiro oxy-cope system and related studies: A new entry into perhydrophenalene and perhydroacenaphthylene systems☆

Abstract The spirovinyl carbinol 5 when treated with methanolic potassium hydroxide was found to rearrange to perhydrophenalene- 1,4-dione 6 via an anionic oxy-Cope rearrangement followed by an intramolecular Michael addition. The epimeric mixture of ketol acetates 15a and 15b was also found to rearrange to 2-hydroxy-2-methyl perhydroacenaphthylene-1,3-dione 16 on treatment with base.

A dianionic oxy-cope rearrangement route to benzotropones - Part XII.

The divinyl carbinols 3 and 6 furnished the benzotropones 4 and 7 respectively, when treated with base.

A transannular reaction in an anionic oxy-cope system9

Abstract The carbinol 8 is found to rearrange to the bicyclo (2,2,2) octane derivative 10 in the presence of base; the rearrangement involves a transannular reaction in a ten membered ring resulting from an Oxy-Cope system.

Base catalyzed rearrangement of oxy-cope systems

The synthesis and rearrangement of the optically active etynyl and vinyl carbinols 3 and 4 are reported. The rearrangements are found to be concerted when carried out with KH-THF and non-concerted with KOH-methanol.

Studies on the sequential claisen rearrangement of methyl-3-arlyloxy- 2-(aryloymethyl)prop-2-enolates

Claisen rearrangement of methyl-3-aryloxy-2-(aryloxymethyl)prop-2-enoates (4) in refluxing N,N-diethylaniline gave 3-(2-hydroxyphenylmethylene) -3,4-dihydro-2H-1-benzopyran-2-ones (6) and 3-methoxycarbonyl-2H-1-benzopyrans(7).

Synthesis of linearly fused tricyclic compounds via thermal oxy-Cope rearrangement

Abstract Linearly fused tricyclic [5.6.5] and [6.6.6] compounds 4, 6, 10 and 12 were prepared from ethynyl and allenyl derivatives of self condensed cycloalkanones 3, 5, 9 and 11 by thermal oxy-Cope rearrangement is described.

Ring enlargement-annulation via thermal oxy-Cope rearrangement

Abstract Thermal oxy-Cope rearrangement of substrates 5,7 and 11 resulted in ring expansion and annulation. The effect of alkene substituents and variation in the ring systems on the reaction has been studied.

A new route to the synthesis of 3-methylenecoumarins-via Lewis acid catalyzed rearrangement of methyl α-aryloxymethylacrylates

Abstract Methyl-α-aryloxymethylacrylates 1a–c have been found to rearrange to furnish the methylenecoumarins 2a–c when refluxed in methylene chloride in the presence of anhydrous AlCl 3 .

Studies in claisen rearrangement : Novel thermal transformation of α-aryloxymethylacrylic acids and their derivatives

Abstract α-Aryloxymethylacrylic acids and their derivatives have been found to undergo some novel thermal transformations leading to the formation of ‘ene’ dimers. The structure of the dimer has been revised on the basis of degradation studies, extensive spectral data and isolation of intermediates.

Synthesis and Mercury (II) Trifluoroacetate Mediated Cyclization of N-Aryl -Allenylmethyl Carbamide

Abstract A three step sequence is described for conversion of substituted phenyl carbamide into 1-cyano-4-methylidene -1,2,3,4-tetrahydro quinoline involving N-propargylation, allene formation followed by mercury (II) trifluoro acetate catalysed cyclization.