Azacycloundecene

The experimental conditions can also affect the stereoselectivity of the M-RCM reaction. For example, the key step of the synthesis of recifeiolide from ester 38 with catalyst GO by Fiirstner and Langemann proceeds in good yield, but the E/Z ratio depends on the temperature of the reaction (Scheme 2.15) [15]. Nakagawa et al. also reported a variation of the E/Z ratio with the reaction temperature during the formation of azacycloundecenes in the presence of Gl it changes from 12.5 1 at 20 °C to 5.2 1 at 50 °C [30],... 

The fourth approach to the synthesis of manzamine C involved a Ramberg-Backlund rearrangement in the key step for the preparation of the azacycloundecene ring [81[. Synthesis ofthis ring began with thecondensationof5-amino-l-pentanol 156... 

The Ramberg-Backlund rearrangement was the key step in the total synthesis of the marine alkaloid manzamine C by D.l. MaGee and E.J. Beck. The azacycloundecene ring was stereoselectively formed by exposing the a-chloro sulfone to a strong base. The use of weaker bases either resulted in no reaction or gave rise to mixtures of ( )- and (Z)-alkenes. 

As mentioned above and, in terms of classification, we will not coimt the j8-carboline system as a cyclic imit. Bearing this in mind, the simplest cycloamine alkaloid foimd so far, a 6Z-azacycloundecene, is keramaphidin C (62). This monocyclic compoimd can be regarded as a plausible key... 

Deoxygenation of Epoxides. Rh -catalyzed deoxygenation of epoxides with dimethyl diazomalonate was shown to occur stereoselectively. This reaction feature was used for efficient inversion of double bond configuration in azacycloundecene fragment in the total s)mthesis of manzamine C (eq 32). ... 

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