And Wagner-Meerwein rearrangements

The Pirrung synthesis is notable for its brevity and clever amalgamation of [2 + 2] photocycloaddition and Wagner-Meerwein rearrangement chemistry Enol ether 757 was reacted with the Grignard rea nt from 5-bromo-2-methyl-l-pentene, subjected to acid hydrolysis, and irradiated to generate the tricycle 738. Wittig olefination of this ketone and treatment with p-toluenesulfonic acid provided racemic isocomene. 

The selectivity was useful in a synthesis of nojigku alcohol (8) from (—)-isobornyl acetate (4). Oxidation of 4 with CrOj gave a mixture of 5 and 6, which was converted into 7 in high yield by Riley oxidation and reduction. The conversion of 7 into 8 involves elimination of the 5-keto group and Wagner-Meerwein rearrangement. ... 

Most ir-nucleophiles employed in iminium ion cyclizations have a predetennined postcyclization destiny. For example, aromatic terminators will rearomatize, organosilanes will eliminate silicon through anticipated pathways and acetals and enol ethers will produce carbonyl compounds. However, the cyclizations of simple alkenes have supplied products that are the formal results of eliminations, additions and Wagner-Meerwein rearrangements. Almost exclusively Mannich-type cyclizations of unsaturated amines have been employed to prepare piperidines. 

A bicyclo[3.2.1] system is synthesized by treating 1,5-cyclooctadiene with antimony(V) chloride in carbon tetrachloride. After initiation by addition of chloronium ion, a sequence of cyclization and Wagner-Meerwein rearrangements leads stereoselectively to the bicycle l13. 

Oxidation of ketosUroids. Oxidation of ketosteroids with this substance involves acetoxylation, dehydrogenation, and Wagner-Meerwein rearrangement. ... 

This reaction is related to the Tijfeneau-Demjanov Rearrangement and Wagner-Meerwein Rearrangement, both involve carbocation intermediates. 

Sdieme 6,59. Representations of the 1,2-hydride migration and Wagner-Meerwein rearrangements on a bicyclic carbocation. 

Roush, W. R., and T. E. D Ambra Synthesis of a bicyclic precursor to verrucarol Application of a trimethylsily-controlled Diels-Alder reaction and Wagner-Meerwein rearrangement sequence. J. Organ. Chem. (USA) 46, 5045 (1981). 

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