A new synthesis of (−)-anisomycin or (+)-anisomycin starting from D-tyrosine or L-tyrosine

A common strategy towards the synthesis of 1,4-dideoxy-1,4-imino-l-xylitol, deacetyl (+)-anisomycin and amino-substituted piperidine iminosugars

A strategy towards the synthesis of three different target molecules, namely 1,4-dideoxy-1,4-imino-l-xylitol, deacetyl (+)-anisomycin and amino-substituted piperidine iminosugars, molecules of potential biological and medicinal significance, is reported from a common amino-vicinal diol intermediate derived from tri-O-benzyl-d-glucal. Construction of the key pyrrolidine ring present in 1,4-dideoxy-1,4-imino-l-xylitol and (+)-anisomycin was a consequence of thermodynamically driven concomitant intramolecular nucleophilic addition reaction of the amino group to the resultant aldehyde obtained by oxidative cleavage of the amino-vicinal diol. Alternatively, double nucleophilic substitution on an amino-diol, after mesylation, with various amines delivered amino-substituted piperidine iminosugars in good yields.

Potassium Carbonate-Promoted Stereospecific 5-Endo-Trig Cyclization of Unactivated Allenes in the Absence of Any Transition Metals

Formation of 3-pyrrolines from simple unactivated allenes bearing a protected amino group under basic conditions is described. Treatment of alpha-amino allenes with potassium carbonate in DMF under reflux in the absence of any transition-metal catalysts gave the corresponding 3-pyrrolines in good to excellent yields, by 5-endo-trig mode cycloisomerization. The reaction of internal allenes with an axial chirality afforded the corresponding 3-pyrrolines in a stereoselective manner.

An aldol-based approach to the synthesis of the antibiotic anisomycin

[reaction: see text] A new approach to the synthesis of the antibiotic anisomycin is reported that relies upon a key aldol disconnection. The glycolate aldol coupling proceeds in 75% yield and with >95% diastereoselectivity, which allows the 13-step synthesis to proceed in 35% overall yield.