PART I: THE REACTIONS OF LITHIATED ORTHO-METHYLARYL T-BUTYL SULFONES WITH 7-THIABICYCLO(4.2.0)-1(8)-OCTENE 7,7-DIOXIDE. PART II: THE TRUCE-SMILES TYPE REARRANGEMENT OF LITHIATED ORTHO-METHYLARYL T-ALKYL SULFONES
Abstract
A number of methyl-substituted o-methylaryl t-butyl sulfones were metalated on the o-methyl group with n-butyllithium in THF at -78(DEGREES)C and found to undergo a Michael addition to the carbon-carbon double bond of 7-thiabicyclo{4.2.0}-1(8)-octone 7,7-dioxide. In some cases the intermediate lithium species underwent an immediate cyclization by displacement of lithium t-butylsulfinate to form a unique class of benzo-fused tricyclic sulfones. Two examples of this cyclized product were desulfurized with Raney nickel to give a novel class of benzo-fused spiro{4.5}decanes. When lithiated o-methylaryl t-alkyl sulfones were heated to reflux in THF they were found to rearrange by migration of the t-alkyl group from sulfur to the lithiated benzylic carbon to form o-alkylbenzenesulfinic acids. This extension of the Truce-Smiles rearrangement was investigated for a number of sulfones and evidence from formation of symmetrical dimeric products in the rearrangement of a cumyl sulfone and unsymmetrical coupling products in a mixture system indicates that the reaction may proceed by a radical, radical-anion mechanism. However, the experimental evidence does not preclude the possibility of a concerted, anionic sigmatropic or pericyclic rearrangement in the t-alkyl migrations. It was also found that o-alkylaryl t-butyl sulfones which metalate on the benzene ring ortho to the sulfone will eliminate lithium t-butylsulfinate on heating to reflux in THF to form o-alkylbenzyne intermediates.
Degree
Ph.D.
Subject Area
Organic chemistry
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