Geminal substituent

Halterman and McEvoy studied hydride reduction of a functionalized 2,2-diarylcyclopen-tanone 8 (Fig. 5) containing an unsubstimted phenyl group and a para-substituted phenyl group, both geminal substituents being assumed to be sterically equivalent [67]. The stereoselective reduction with sodium borohydride of a... 

Two Geminal Substituent Groups Attached at the Skeletal Phosphorus Atoms... 

Geminal substituents in multiply substituted compounds present the situation of closest mutual proximity. For that reason it is often difficult, if not impossible, to separate steric from electronic contributions to nonadditivity effects (NAEs, ICSs). A predominance of steric contributions to the ICS is expected when at... 

Additional studies, concerning the influence of 1,2-allylic strain caused by a geminal substituent near the stereogenic centre of allylic alcohols , showed that it does not effectively compete with 1,3-allylic strain in differentiating the diastereoselectivity of the... 

The presence of capto-dative geminal substituents as in 24 facilitates the cyclodimerization process. A similar observation was made when a ji-conjugating group was substituted at the methylene carbon such as in 26.14... 

Table 4.81 shows the empirical increments obtained for substituents in position i relative to an olefinic carbon denoted as k. Correction terms S are required for cis and geminal substituents. As an application of the increments in Table 4.81 the olefinic carbon shifts of (Z)-4-methyl-2-pentenoic acid are predicted ... 

Actually, steric hindrance between geminal substituents of a dioxetane (3,3-steric interaction) appears to especially stabilize the peroxidic ring [6d], Conversely, the presence of an easily oxidized substituent, that has low... 

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