The addition of nucleophiles to R-chiral allyl chlorides via a SN2¢ mechanism also follows, in principle,
the Felkin-Anh rule as discussed for the addition of nucleophiles to R-chiral carbonyl compounds; however,
some important differences again apply. Accordingly, the Felkin conformation 140 leading to the
adduct 138 should be favored; however, in the case of (Z)-configurated alkenes 137, the anti-Felkin
conformation 141 increases in importance in order to minimize 1,3-allylic strain (Scheme 41). Therefore,
excellent Felkin diastereoselectivity is found for the addition of cuprates to (E)-137 (Table 21, entries
1-8)62 while with (Z)-137 the stereoselectivity is somewhat diminished (entries 9-10). Surprisingly,
alkoxy substituents do not seem to exert the stereoelectronic effect seen earlier by the addition to arbonyl compounds.