The Absolute Configuration of Muamvatin
A degradation product 2 of muamvatin has been synthesized starting from the stereodefined building blocks 7 and 9. This synthesis allowed assignment of the absolute configuration of muamvatin as well as of the relative configuration at all stereocenters except for C-11. The latter configuration is proposed on the basis of the 1H-NMR data of natural muamvatin. Attempts have been made to clarify the configuration at C-11 of muamvatin by synthesis starting from the aldehyde 9 and the ketones 28.