3-Bromo-levoglucosenone

A Diels-Alder reaction between 3-bromo-levoglucosenone and butadiene gives rise to adduct (10), which could be converted into (11), which represents the guanidinium part of tetrodotoxin. An interesting intramolecular Diels-Alder reaction (Scheme 3) was a key step in a synthesis of (+)-isovelleral (12) from the L-erythuronic acid derivative (13) which is accessible from D-ribonolactone. The synthesis produced firstly the diastereomer (14) of (-f-)-isovelleral (12), but the two were thermally interconvertible by an ene-type opening and closing of the three-membered... 

Bromo-levoglucosenone 31 provides a functionalized dienophile which undergoes cycloaddition to give, after straightforward manipulation, ketone 32. The hindered ketone unit of 32 underwent nucleophilic attack using an alkynylborate complex in a synthetic approach directed towards tetrodotoxin (Scheme 6). Ketone 32 was found to be extremely sensitive and the precise nature of the alkynyl nucleophile was crucial to the success of the key addition step. ... 

The preparation and chemical properties of levoglucosenone as well as its use in the total synthesis of natural products have been reviewed, and the stereoselective reduction of 3-bromolevoglucosenone to l,6-anhydro-3-bromo-3,4-dideoxy-P-D-rAreo-hex-3-enopyranose 1 has been effected using zinc borohydride. The known lactone 2 has been converted into the aldosulose derivative 3, a degradation product from the ansamycin antibiotic (+)-trienomycin A. This confirmed that the fragment of the natural product was the enantiomer of 3. ... 

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