Sugar allyltin derivatives

Sugar allyltin derivatives are very useful synthetic intermediates. The most convenient and reliable method for their preparation is a so-called xanthate procedure. The first compound of this class was prepared in 1988 by Mortlock and Thomas [74]. 1,2-0-isopropylidene-D-glycer-aldehyde (80) was converted into allylic alcohol and further transformed into the corresponding xanthate 81. This compound underwent thermal [3,3] rearrangement into the dithiocarbon-ate 81a, which upon reaction with tri-n-butyltin hydride provided the final sugar allyltin 82 as a mixture of isomers with the E-one strongly predominating (O Scheme 35). 

Jarosz, S., and Skora, S., A convenient route to enantiomerically pure highly oxygenated decalins from sugar allyltin derivatives. Tetrahedron Asymmetry. 11, 1433, 2000. 

Reaction of aldohexofuranose 5,6-diols with TPP/imidazole/l2 has afforded the corresponding 5,6-unsaturated derivatives, while elimination of HBr from the 6-bromo compound 23, followed by hydroboration, has generated the product 24 with the L-ido configuration (Scheme 4). Some sugar allyltin derivatives (e.g. 

Sugar allyltin derivatives, convenient precursors of dienoaldehydes such as compounds 31, have been obtained by Sr2 reaction of trialkyltin radicals with allylic thiocarbonates which were, in turn, produced by Wittig condensation followed by a 3 3 thermal rearrangement, as shown in Scheme 5. ... 

Intramolecular Diels-Alder reaction of chiral highly oxygenated trienoates derived from sugar allyltins [75]... 

An interesting approach to carbobicyclic polyhydroxylated compounds was proposed by Jarosz.43 It was based on a Lewis acid transformation of sugar allyltins 82 into dieno-aldehydes 83 with the fi-geometry across the internal double bond exclusively. The Wittig-type reaction of 83 afforded a triene, which underwent cyclization under high pressure, providing derivatives of bicyclo[4.3.0]nonane 84. Alternatively, dienoaldehyde 83 was converted into the phosphonate 85, which afforded the bicyclo[4.4.0]-decene derivatives (86) upon reaction with an aldehyde and simultaneous cyclization of the resulting triene.43 (Fig. 29). 

Application of allyltin derivatives in organic synthesis is well documented [46-48]. Although the reports on the use of normal allyltins appeared already in the 1970s, the sugar analogs were introduced to the chemical literature almost two decades later. In 1988, Mortlock and Thomas reported the first preparation of such compound derived from glyceraldehyde [49]. Soon after that first paper, we proposed the synthesis of more complex organometallics from D-hexoses [41, 50]. 

Trost and coworkers developed a chiral zinc phenoxide for the asymmetric aldol reaction of acetophenone or hydroxyacetophenone with aldehydes (equations 62 and 63) . This method does not involve the prior activation of the carbonyls to silyl enol ethers as in the Mukaiyama aldol reactions. Shibasaki and coworkers employed titanium phenoxide derived from a phenoxy sugar for the asymmetric cyanosilylation of ketones (equation 64). 2-Hydroxy-2 -amino-l,l -binaphthyl was employed in the asymmetric carbonyl addition of diethylzinc , and a 2 -mercapto derivative in the asymmetric reduction of ketones and carbonyl allylation using allyltin ° . ... 

---