title: Hydrazulene ring systems via heteroatom-assisted [1,2]-shift of oxonium and sulfonium ylides.
abstract: [reaction: see text] Cyclic mixed acetals with pendant diazoketone side chains undergo rearrangement to ether-bridged cycloheptane ring systems on treatment with Cu(hfacac)(2). Stevens [1,2]-shift of an oxonium ylide furnishes the major product (7), in some cases accompanied by minor amounts of a product (8) resulting from [1,2]-shift of a sulfonium ylide. In the subsequent sulfur-triggered cleavage of the bridging ether, the desired bicyclo[5.3.0]heptene was obtained, along with the product of novel S(N)2' attack on the resulting allylic ketal.
authors.affiliation: Department of Chemistry, University of Alberta, Edmonton, AB, Canada T6G 2G2.
authors.forename: Graham K
authors.initials: GK
authors.lastname: Murphy
authors.forename: F G
authors.initials: FG
authors.lastname: West