41527-58-6Relevant articles and documents
Photocycloaddition of 3-alkenyloxy-2-cycloalkenones: Enantioselective lewis acid catalysis and ring expansion
Brimioulle, Richard,Bach, Thorsten
, p. 12921 - 12924 (2014)
By application of substoichiometric amounts (50 mol %) of a chiral Lewis acid, the intramolecular [2+2] photocycloaddition of the title compounds was achieved with high enantioselectivity (up to 94 % ee). Upon cleavage of the cyclobutane ring the resulting tricyclic products underwent ring-expansion reactions under acidic conditions and formed anellated seven- or eight-membered-ring systems without racemization. The ring expansion could be combined with a diastereoselective reduction (triethylsilane) or allylation (allyltrimethylsilane) upon BF3 catalysis (48-87 % yield). Ring-a-ring o'roses: An enantioselective, Lewis acid catalyzed [2+2] photocycloaddition (9 examples, 69-94 % yield, up to 94 % ee) leads to tricyclic products, in which the marked bond of the cyclobutane ring can be cleaved to form medium-sized rings as shown in the example above.
Intramolecular Photocycloaddition of the 3-(3-Butenyloxy)-2-cyclohexenone System
Umehara, Takashi,Inouye, Yoshinobu,Kakisawa, Hiroshi
, p. 3492 - 3494 (2007/10/02)
The irradiation of 5,5-dimethyl-3-(4-methyl-3-pentenyloxy)-2-cyclohexenone gave regioselectively, 6,6,10,10-tetramethyl-2-oxatricyclo1,5>undecan-8-one, while, that of 5,5-dimethyl-3--2-cyclohexenone afforded, regio- and stereoselectively, 1,5,5-trimethyl-8-oxatetracyclo2,7.01,5>tetradecan-3-one.
