Bicydo 3.3.0 octenes

Another option is the twofold Michael addition/SN-type sequence of which manifold versions have been published. Thus, Padwa s group reported on the di-astereoselective synthesis of bicydo[3.3.0]octenes [199], while in another approach by Hagiwara and coworkers various tricyclo[3.2.1.0]octane derivatives and similar bridged compounds have been constructed [200]. The group of Spitzner has also been engaged intensively in Michael/Michael/SN-type processes [201]. One such ex-... 

Tctramethyl-3-tert.-butyl-.. . 7,7,10 J0-Tetramethyl-4-tert.-butyl-tri-cydo[4.4.0.02 dean-iP) +2,2,5,5-Tetramethyl-7-(3,3-dimethyl-buten- (l)-yl-bicydo[4.2.0 ]octen-(P) (17 83) — ... 

VIII endo-5,endo-(i-Dimfithyl-bicydn[2.2.2]oden-(2)-5,G-dtcarbonsdure-anhydrid P 245° IX exo-7,exo-8-Dimethyl-bicydo[4. 2.0 octen-(2)-7,8-dicarbonsdure-anhydrid F 101°... 

Tetra- methyl-cyelo- hexadien-(l,3) (/3-Pyronen) + Dimethyl- maleinsaure- anhydrid 100 ml + 10 g 6 g Benzo-phenon 100 ml Benzol 20° 4 Tage n 2,3,4,4,7,8-Hem-methyl-bicydo [4.2.0]octen- 2)-7,8-dicarbon-saureanhydrid 66 130 1... 

Analog erhalt man 7-Amino-8-oxo-3,5-dimethyl-2-benzyloxycarbonyl-4-oxa-l-aza-bicydo[4.2.0]octen-(2) (74% d.Th. F 96-97°)2 und verschiedene 7-Amino-8-oxo--2-alkoxycarbonyl-4-thia-7-aza-bicyclo[4.2.0]octene3 (70-99% d. Th.). 

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