Potentially participating group

Directing Effect of Potentially Participating Groups at Remote Positions of Donors... 

Unlike the neighboring group participation by 0-2 protecting groups, the existence of the remote participation by potentially participating groups at remote positions of glycosyl donors has been controversial. We reviewed reports that were opposed to and in favor of the remote participation. Nevertheless, results and evidence in favor of the remote participation are quite substantial, especially for... 

The review aims at providing a general overview of stereocontrolling properties of remote potentially participating groups. However, in spite of plenty of pubhshed... 

The cooperative effect of participating substituents at 0-4 and 0-3 in fucosyl donors was also shown forp-N02Bz groups [45-48]. Historically, these works were the first where donors with remote potentially participating groups were used. 

Scheme 5.28 The absence of 3-directing influence of potentially participating groups at 0-4 in mannosyl donors.

Demchenko et al. [62] investigated different potentially participating groups, either carbonyl or tbiocarbonyl, at 0-4 of thiomannosides 96 by comparison with fully benzylated thioglycoside 93 but found almost no influence (Scheme 5.28). 

Sulfonyloxy groups may undergo bimolecular replacement reactions with nucleophiles, either external or internal, according to their axial or equatorial disposition and/or potential neighboring-group participation. 

Y c Potential Leaving Group Z s Participating or non-participating group... 

Despite the early recognition that heterocyclic azadiene systems are typically electron-deficient,1 little effort has been devoted to the exploration of the potential participation of electron-deficient oxazoles in inverse electron demand (LUMOdiene controlled) Diels-Alder reactions with electron-rich or simple olefinic dienophiles. One study has demonstrated the potential of such investigations (Table 10-1, entry 26).34 Breslow and coworkers have adapted the oxazole olefin Diels-Alder reaction for the preparation of a tetrahydroquinoline-based analog of pyridoxamine with the stereochemically defined placement of a catalytic group [Eq. (2)].37b... 

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