Cyclopropyl rearrangement

Tetrazolate, 5-(3-chlorobenzyldimethylammonium)-structures, 5, 796 Tetrazolate, 5-cyclopropyl-rearrangement, 5, 810 Tetrazolate, 5-(p-substituted)phenyl-alkylation, 5, 818 Tetrazolates anions... 

With TS-1, nearly equal amounts of trans- and ds-l,3-dimethylcyclopentanol were obtained from the first type of probe, while no rearranged products were obtained with the second ones. These results suggest that the putahve radical intermediate is very short-lived, but not short enough to prevent the racemizahon of the terhary carbon radical. Incidentally, it was estimated that epimerizahon and cyclopropyl rearrangement occurred with first order rate constants of 10 and ca 10 s , respectively [30, 31]. 

Starting from (Z)-undeca-l,5-dien-3-ol a biogenetic-type synthesis of (+ )-dictyopterene A was achieved using the homoallyl-cyclopropyl rearrangement as the key step for cyclopropyl formation. Solvolysis of (Z)-3-mesyloxyundeca-l,5-diene under a variety of conditions failed to give cyclopropylmethyl compounds due to the presence of the terminal double bond. In contrast, (Z)-3-mesyloxy-l-(phenylthio)undeca-5-ene (3) afforded a mixture of epimeric cyclopropyl-methanols 4 in 91 % yield. Appropriate functional group transformation eventually leads to the desired dictyopterene A. 

The (cyclopropylamino)carbene complex 15 reacted with diphenylalkyne to give a nitrogen ylide, which was converted via thermal A -cyclopropyl to C-cyclopropyl rearrangement and decomplexation to a cyclopropyl-substituted lactam. 

The rearrangement products (359) and (360) are obtained on oxymercura-tion of cyclodeca-l,2,5,8-tetraene (361). A bridged intermediate (362) is suggested homoallyl-cyclopropyl rearrangement leads to (363), a metal-complexed carbene which is known to undergo hydride shifts as indicated. This mechanism is supported by deuterium labelling. ... 

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