159146-91-5Relevant academic research and scientific papers
Tetrasubstituted Furans from Novel Photocycloaddition of Conjugated Acetylenic α-Diketones with Alkenes
Mukherjee, Ashis K.,Agosta, William C.
, p. 1821 - 1822 (1994)
Photocycloaddition of ketones 1a - c with tetramethylethylene 2 furnishes tetrasubstituted furans 3a - c in isolated yields of ca. 85percent; a suggested mechanism for formation of 3a involves cycloaddition by way of an initial biradical 5 to form
Photoaddition of alkenes to conjugated α-diketones: Tandem cyclizations leading to tetrasubstituted furans
Mukherjee,Margaretha,Agosta
, p. 3388 - 3391 (2007/10/03)
Photocycloaddition of 9a-c with 2 leads cleanly to tetrasubstituted furans 12a-c, respectively, in yields of ~85%. The reactive triplet is efficiently sensitized by 2-benzoylnaphthalene and quenched by anthracene, indicating that E(T) is in the range 43-58 kcal/mol. A mechanism is proposed involving an alkyl propargyl biradical (as 10) that closes first to a vinyl carbene (as 11) and then to product. Reaction of 9c with 20 furnishes only 22, and this result rules out an alternative mechanism in which the order of steps leading to the carbene is reversed.
