Of valienamine

Acid hydrolysis of the epoxide (233) obtained from 46 gave, after acetylation, the acetate (234), which, on treatment with DBU, yielded the diene (235), useful for preparation of the azides (237 and 238), the precursors of valienamine analogs. Treatment of 46 with DBU in toluene resulted in... 

Applications to natural product synthesis probe the limits of any synthetic method, as situations arise that would never have been considered in the course of first developing the method. Recent syntheses of valienamine 6, agelastatin 9 and tonantzitlolone 15 pressed the limits of ring-closing metathesis. 

In summary, the novel synthesis of (+)-valienamine and (+)-validamine has been accomplished by our synthetic strategies for the constructing of carbasugars. The absolutely stereoselective hydrogenation of 26 and 27 to give (+)-validamine (29) is particularly noteworthy. 

In spite of the great biological potential of valienamine and its derivatives, only a few methods have been reported for their synthesis [56]. 

Knapp, S. et al. Intramolecular Amino Delivery Reactions for the Synthesis of Valienamine and Analogues. 3.4.3 1992 [138]... 

Trost, B.M. et al. Total Synthesis of ( )-Valienamine and (+)-Valienamine via a Strategy Derived from New Palladium-Catalyzed Reactions. 3.4.3 1998 [183]... 

The alkylation of a dibenzoate with (phenylsulfonyl)nit-romethane gave an intermediate for the synthesis of (+)-valienamine. ... 

Knapp, S, Naughton, ABJ, Dhar, T G M, Intramolecular amino delivery reactions for the synthesis of valienamine and analogues. Tetrahedron Lett., 33, 1025-1028, 1992. 

P. Kapferer, F. Sarabia, and A. Vasella, Carbasaccharides via ring-closing alkene metathesis. A synthesis of valienamine from D-glucose, Helv. Chim. Acta, 82 (1999) 645-656 4043-4052. 

The iodosyl elimination has been used in the preparation of unsaturated oxazolidinone 635 (Scheme 3.248), the key intermediate in the synthesis of valienamine [662], This reaction proceeds via oxidation of iodide 633 to the intermediate iodosyl compound 634, which spontaneously eliminates HOI to afford product 635. The Reich iodosyl yyn-elimination has also been used for the preparation of intermediate steroidal units of cephalostatin 7 [663],... 

Sulfonylnitromethane (92) is an interesting nucleophile, which undergoes double substitution. Double C-, and 0-allylation of 92 with me5 0-3,6-dibenzoyloxy-cyclohexene (91) provided the enantiomerically pure heterocycle 93 in 87 % yield, and asymmetric synthesis of valienamine was achieved [37]. 

A low yielding synthesis of 2-acetamido-5a-carba-2-deoxy-a-D,L-a//o- and gwlo-pyranose tetraacetates and some 3-acetamido-3-deoxy derivatives have been achieved starting from bicyclic acetate 87." By use of the same intermediate the preparations of valienamine and valiolamine have also been achieved." ... 

In a complex paper reporting over 86 compounds, Paulsen and Heiker, have reported a twenty-step synthesis of valienamine (34) from quebrachitol (L-2-O-methyl-chlro-inosltol) (35) (Scheme 11). 

A series (24 compounds) of N-substituted valienaraines (50), which are cx -glycosidase inhibitor analogues of valienamine (50, R=H), have been synthesized. N-Alkyl and N-aralkyl derivatives all showed inhibitory activity, some more than the parent compound. By contrast N-acyl derivatives either lack activity or... 

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