Highly hindered and sensitive isocyanates react with alcohols under mild catalysis by titanium tetra-t-butoxide to give high yields of the corresponding carbamates.

We describe the syntheses of (+)-euphococcinine and (-)-adaline, two naturally occurring alkaloids containing a quaternary carbon bearing a nitrogen atom. Key features of the syntheses are a 3,3-sigmatropic rearrangement to give an all-carbon quaternary center, a ring-closing alkene metathesis to give an 8-membered ring, and the use of a single enantiomer of p-menthane-3-carboxaldehyde to make two natural alkaloids of opposite configuration.

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