Triple self-condensation of fused cycloalkanonylparacyclophanes promoted by titanium tetrachloride and triethylamine

Butterflyene: an entry into an aesthetically pleasing carbocycle via a Diels-Alder reaction on a tetrasubstituted olefin

An interesting molecular architecture, butterflyene, resembling the shape of a butterfly has been synthesized via a sequence of cyclocondensation, benzylic oxidation, McMurry coupling and Diels-Alder reaction (DAR), successively. The DAR of the tetrasubstituted double bond of a bicyclopentylidene moiety with various dienes has been performed to prepare the analogues of butterflyene. DFT calculations have also been used to analyze the structural optimization and reaction energies.

Room-Temperature Synthesis of 1,3,5-Tri(het)aryl Benzene from Nitroalkenes Using Pd(OAc)2: Complete Mechanistic and Theoretical Studies

Herein, a room-temperature catalytic pathway for 1,3,5-tri(het)aryl derivatives from nitroalkenes using simple Pd(OAc)₂ is presented. This newly developed C-C bond-forming methodology takes place in a cascade manner with the initial pallado-Morita-Baylis-Hillman (MBH) type adduct. The broad substrate scopes, functional group tolerance, and different aryl-substituted benzene derivatives make this methodology more attractive. Furthermore, the mechanistic understanding through isolation of intermediates and DFT studies of the catalytic cycle provide requisite insight into the methodology.

The synthesis of lactone-bridged 1,3,5-triphenylbenzene derivatives as pi-expanded coumarin triskelions

Two triply lactone-bridged 1,3,5-triphenylbenzene derivatives with solubilizing moieties have been synthesized in five and six steps from commercially available starting materials. Compounds containing the 1,3,5-triphenylbenzene core with two atom bridges are relatively unknown. This new class of pi-expanded coumarins contain triskelion architectures and X-ray crystallographic studies of one of the triskelions indicates that the 1,3,5-triphenylbenzene core adopts a near-planar geometry. This is the only known example of a two atom-bridged 1,3,5-triphenylbenzene derivative to adopt a planar structure.

Trisannulated benzene derivatives by Acid catalyzed aldol cyclotrimerizations of cyclic ketones. Methodology development and mechanistic insight

Several factors that contribute to the success of aldol cyclotrimerizations have been clarified as part of an effort to shed light on the inner workings of this century old reaction. The use of 4,7-di-tert-butylacenaphthenone (11) as a mechanistic probe molecule has led to intriguing discoveries about temperature, solvent, and solubility effects. Solvents that are both polarizable and somewhat polar, e.g., o-dichlorobenzene (ODCB), work best for the aromatic ketones examined. Certain Brønsted acids were found to work better than Lewis acids as catalysts for the archetypal aldol cyclotrimerization of indanone (2) in aprotic solvents, and a strong dependence on the pKa of the acid was observed. A standardized protocol, using p-toluenesulfonic acid monohydrate, is shown to work well in a number of test cases.