Application of photochemical decarbonylation of cyclopropenones for the in situ generation of reactive enediynes. Construction of a cyclopropenone-containing enediyne precursor by using a cyclopropenone acetal building block.
[reaction: see text] A cyclopropenone-containing enediyne photoprecursor, 6-tert-butyldimethylsilyloxy-3-(alpha-hydroxybenzyl)bicyclo[8.1.0]undeca-1(10),2-diene-4-yn-11-one (1), was prepared in 10 steps by sequential modification of the cyclopropenone 2,2-dimethyl-1,3-propanediyl acetal (5). The crucial cyclization step was achieved under Nozaki conditions, while the endocylic double bond has been introduced by the allylic rearrangement. UV irradiation of the cyclopropenone 1 results in efficient decarbonylation and the formation of the reactive enediyne 2. The latter undergoes Bergman cycloaromatization with a half-life of 12 h at 40 degrees C and in the presence of 1,4-dihydrobenzene quantitatively produces corresponding tetralin 29.
Poloukhtine
Andrei
A
Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA.
Popik
Vladimir V
VV
D000080:Acetals / Q000737:chemistry*; D001554:Benzene / Q000737:chemistry; D003500:Cyclization; D003521:Cyclopropanes / Q000138:chemical synthesis / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry; D007700:Kinetics; D008745:Methylation; D015394:Molecular Structure; D010777:Photochemistry; D013057:Spectrum Analysis
D000080:Acetals; D003521:Cyclopropanes; D006878:Hydroxides; C120343:cyclopropenone; C031356:hydroxide ion; D001554:Benzene