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Fisher chromium carbene complex

Sugar acetylene reacted with a Fisher chromium carbene complex to give a phenol derivative, a possible intermediate for naturally occurring aryl-C-glycoside antibiotics (O Scheme 34) [55]. [Pg.778]

Harrity and co-workers described the application of 2-substituted 1-alkynylboronic esters in the Dotz cycloaddition of Fisher chromium carbene complexes, affording in a highly regioselective fashion a novel class of hydroxy-naphthyl boron pinacolates (entry 18, Table 1.3) [217]. These reaction products also provided, upon treatment with ceric ammonium nitrate, the corresponding quinone boronic esters. [Pg.36]

While Fischer carbene omiplexes tend not to react widi unactivated alkenes, many chromium and molybdenum Fisher carbene complexes do mtmocydoprtqianate 1,3-dienes in good yield with high levels of chemo-, regio-, and stereoselectivity... [Pg.226]

Another synthetic pathway to seven-membered rings is by reacting chromium Fisher carbene complexes with... [Pg.22]

The imine bond in 2-imidazolines reacts with Fisher carbenes under irradiation (Scheme 144). Low yields were obtained with monosubstituted imidazolines 608a-c due to thermal decomposition of the substrates under the reaction conditions. Optically active 4,4-disubstituted A -imidazolines 608d-e form azapenams (609d, 610e, 611) with (methoxymethylcarbene)chromium complex in good yields and high diastereoselectivity. The electronic nature of RVR clearly influences the sense of diastereoselectivity (609 vs. 610, 611) <1977JOC3586>. [Pg.232]


See also in sourсe #XX -- [ Pg.778 ]




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