SENBOKU Hisanori Hokkaido Univ., Instructor (Fac.of Engineering), 工学部, 助手 (50241360)
ORITO Kazuhiko Hokkaido Univ., associate Professor (Fac.of Engineering), 工学部, 助教授 (20109482)
TOKUDA Masao Hokkaido Univ., Associate Professor (Fac.of Engineering), 工学部, 助教授 (80001296)
New Photoadditions of quinones leading to heterocyclic quinones. -A one-step formation of heterocyclic quinones by a new regioselective [3+2] photoaddition of 2-hydroxy, 2-amino-, and 2-mercapto-1,4-naphthoquinones with a variety of alkenes, alkyns and naphthol was found. The new [3+2] photoaddition reaction was then applied to the synthesis of maturinone. New photoacylation and alkylation of 2-arylamino-, and 2-alkylaminonaphtho quinones were also devised.
Development of new methods for the transformations based on selective fragmentation of alkoxyl radicals.-Several new methods were devised for the synthesis of bicyclo[5.4.0]undecane skeleton, lignans, phthalides, sesquiterpenes, and gamma- and delta-lactones based on selective beta-scission of alkoxyl radicals. These methods were successfully applied to the total synthesis of several terpenoids and lignans such as ((〕SY.+-.〔))-caryophyllene, ((〕SY.+-.〔))-isocaryophyllene, ((〕SY.+-.〔))-himachalene, ((〕SY.+-.〔))-recifeolide, ((〕SY.+-.〔
))-eudesmin, ((〕SY.+-.〔))-piperitol, and ((〕SY.+-.〔))-yangambin.
New Selective photochemical reactions of unsaturated cyclic ketone oximes. -New stereospecific photoaddition of methanol and photoisomerization involving stereospecific photoaddition of proton were found and the mechanisms of the processes were established on the basis of deuterium-labelling studies.
New stereoselective synthesis of 2,5-disubstituted pyrrolidines by electrochimecal, anionic, or radical cyclization of species generated from delta-alkenylamines.-Anodic oxidation of lithium amides of 1-and/or 5-substituted N-methyl-delta-alkenylamines or the treatment of 1- or 1,5-disubstituted N-methyl-delta-alkenylamines with a catalytic amount of butyllithium gave cis-N-methyl-2,5-disubstituted pyrrolidines stereoselectively in good yields while the trans-N-alkyl-2- and/or 5-substituted pyrrolidines are stereoselectively formed in high yields by heating a solution of N-chloro-delta-alkenylamines. New total synthesis of (-)-N-methylanisomycin by the anodic cyclization of delta-alkenylamine was achieved.
Other results-A new electrochemical preparation of reactive zinc metal and its application to the facile and efficient isoprenylation of aldehydes and ketones were devised. The method was then applied to the new synthesis of pheromones such as ipsenol and ipsdienol. Less