Elaiophylin , total synthesis

In the first total synthesis of elaiophylin (azalomycin B 181), glycosidation of P-hydroxy ketone 178 and glycal 177 was examined (Scheme 26) [111]. NBS-promoted glycosidation [112] followed by debromination with -Bu3SnH-AIBN was first applied to give 179 in only a 30% yield. Then, the Wakamatsu procedure using CSA-MS 4A [113] was found to afford the desired 179 in 80% yield as the sole anomer, which led to 181 via aldol reaction of the (Z)-boron enolate of the ketone 179 with dialdehyde 180. 

Total syntheses of the following antibiotics and/or their aglycones are dealt with methymycin, erythromycin, pikromycin, oleandomycin, ingramycin (albo-cycline), carbomycin B, leucomycin A3 (josamycin), tylosin, mycinamicins, rosaramicin, A26771B and elaiophylin (azalomycin B). Since the total synthesis of the macrolide-like immunosuppressant FK-506 has been recently reported, it is also reviewed here. Today, erythromycin A, oleandomycin, leucomycin A3 (josamycin), tylosin and mycinamicin II are clinically important antibiotics. 

The First Total Synthesis of Elaiophylin (Azalomycin B) [Kinoshita-Toshima-Tatsuta, 1986, 1988] (Scheme 26) [47, 48]... 

Scheme 6. The challenges in accomplishing di tereoselective aldol couplings during the late stages of a total synthesis as shown by Kinoshita s route to elaiophylin (66). (1986) °...

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