Synthesis from D-sorbitol

Treatment of 74 with 75 in the presence of borontrifluoride etherate followed by hydrolysis afforded 76 and 77. Swern oxidation of 77 gave 78, which on treatment with acetic acid afforded (-)-sesbanimide A (2) in 17% overall yield from the aldehyde 67. The analogue 80 was similarly prepared from 76, via compound 79. 

The diacetate 84 underwent deacetylation followed by acetal formation to afford 85. Selective opening of the cyclic acetal ring followed by Collins oxidation afforded the aldehyde intermediate 86. Treatment of 86 with allylsilane derivative 87 afforded a mixture of diastereoisomeric alcohols 88 in a 1.7 1 ratio. The major product 88 was oxidized to the corresponding ketone 89, which upon removal of the protecting groups led to the formation of (-)-sesbanimide A (2). 

Synthesis of the natural (+)-sesbanimide A (1) from D-xylose, employing a similar method to that used above for 2, has been achieved starting with 43. 

Valverde, S. Garcia-Ochoa, S. Martin-Lomas, M. Carbohydr. Res. 147 (1986) Cl. 

Sugiyama, T. Sugawara, H. Watanabe, M. Yamashita, K. Agric. Biol. Chem. 48 (1984) 1841. 

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