Central and lateral bicyclo[1.1.0]butane bond cleavage with subsequent Wagner-Meerwein rearrangements or carbene formation in the 185-nm photolysis of tricyclo[3.1.0.02,6]hexane, tricyclo[4.1.0.02,7]heptane, and tricyclo[5.1.0.02,8]octane

Deuterium Kinetic Isotope Effects and Mechanism of the Thermal Isomerization of Bicyclo[4.2.0]oct-7-ene to 1,3-Cyclooctadiene

“…Unlabeled cis -bicyclo[4.2.0]oct-7-ene ( 1 ) was prepared through two routes. Photoisomerization of cis , cis -1,3-cyclooctadiene ( 2 ) in heptane in the presence of acetophenone as a sensitizer, followed by preparative GC isolation, gave an authentic sample of 1 . , It was also secured from the [2 + 2] cycloadduct of cyclohexene and dichloroketene, 8,8-dichlorobicyclo[4.2.0]octan-7-one ( 4 ), using the route outlined in Scheme as a run-through for analogous sequences affording labeled analogues. When the methods of Greene and co-workers and syntheses of various deuterium-labeled bicyclo[3.2.0]hepta-2,6-dienes developed by Belfield were followed, ketone 4 was reduced with NaBH 4 and the epimeric mixture of alcohols produced was converted to the corresponding mesylates ( 5 ).…”

Techniques and applications of far-UV photochemistry in solution. The photochemistry of the C3H4 and C4H6 hydrocarbons

“…Presumably,[1,2]-H migration is blocked in these cases because such a process would yield anti-Bredt cyclobutenes of the general structure 93. This <ch2),93…”

“…88 Adam and his group have recently reported the photochemistry of the series of tethered bicyclo [1.1.01butanes (85-87; eqs [40][41][42]. 93 These experiments were 0 pentane 6*0 all performed using an unfiltered low-pressure mercury lamp (185 + 254 nm) as the excitation source, which leads to complications owing to secondary photolysis of the highly photoactive (at 254 nm) 1,3-cycloalkadiene products (observed from 85 and expected from 86 and 87). Control experiments in which 1,3-cyclohexadiene (89) was photolyzed with 254-nm light showed that this diene is converted to a mixture of Eand Z-90, in agreement with previous reports for the photochemistry of this compound.100…”

Controlled Polymerization of a Cyclic Diene Prepared from the Ring-Closing Metathesis of a Naturally Occurring Monoterpene

“…The secondary product isobutene is also polymerizable and enhances the atom economy of our overall strategy. Previous reports describing the synthesis of 2 are not of preparative value …”

“…Previous reports describing the synthesis of 2 are not of preparative value. 9 Radical, 10 anionic, 11 and cationic 12 polymerizations of 2-methyl-1,3-pentadiene, an acyclic structural analogue of 2, are known. In each case, the polymer obtained was of mixed regio-and stereochemistry.…”