regioselectivity with respect to copper-catalyzedconjugateadditions of various Grignard reagents to cyclic enynones. The use of Cu(OTf)2 and NHC ligand L1 as the catalyst combination in CH2Cl2 led to the unique formation of the 1,4 adduct. This selectivity does not follow the general trend previously observed in the literature using extended Michael acceptors. Moreover these reactions allowed for the creation
Single step formation of novel tricyclic systems on [3 + 2] photocycloaddition of 3-(1-alkynyl)cyclohexenones to methoxyalkenes
作者:Paul Margaretha、H.-J Rathjen、William C Agosta
DOI:10.1016/s0040-4039(00)89034-6
日期:1990.1
Irradiation of 1b (λ350 nm) in tert-butyl alcohol solution containing 5 leads to the novel ring system 9b in a single step. Similar reactions occur between 1a and both 5 and 6. Mechanisms of these transformations are discussed.
Novel (3 + 2) photocycloadditions with 3-(1-alkynyl)cyclohexenones and tetramethylethylene
作者:Paul Margaretha、H. J. Rathjen、Steven Wolff、William C. Agosta
DOI:10.1039/c39880000841
日期:——
Irradiation of 3-alkynylcyclohexenones (3) with tetramethylethylene gives rise to novel (3 + 2) cycloadducts that can be explained mechanistically in terms of closure of an initial biradical (6) to a vinyl carbene (7), followed by stabilization of the carbene.