The chiral pi-allylpalladium complex 2a, prepared from exoethylidenenorpinane 7, catalyzed the allylation of diverse imines with allyltributylstannane in the presence of 1 equiv of water in good to high enantioselectivities. The catalyst prepared from a 1:1 mixture of (E)- and (Z)-7 was found to be consisting of two stereoisomers 2a and 2b in 1.3:1 ratio. On separation, 2a catalyzed the allylation of imines in much higher enantioselectivities than 2b, giving the same major enantiomer and thereby justifying the need to separate 2a free of 2b. We have achieved the highest separation ratio of >400:1 for 2a:2b by repeated recrystallizations. Isomerization of 2b to 2a during recovery of 2a from the filtrates was observed as more of 2a was recovered each time during recrystallization. Although dry THF was the best solvent, we tried various additives and found that addition of one equivalent of water gave the best results with respect to shorter reaction time, higher yields and enantioselectivities. Thus, we have developed a more general, reproducible, robust and a non-Lewis acid catalyzed procedure for catalytic asymmetric allylation of imines under essentially neutral conditions.

This review accentuates the recent developments in the Wacker oxidation from its conventional form to the more efficient, economical and greener method established in last five years (2015-2020). The Wacker...

A mimic of the Wacker process for C═O bond formation in terminal olefins can be initiated by a combination of the Pd(II) and hypervalent iodine reagent, Dess-Martin periodinane to generate methyl ketones. This operationally simple and scalable method offers Markovnikov selectivity, has good functional group compatibility, and is mild and high yielding.

An efficient seven-step, protecting-group-free first total synthesis of chatenaytrienin-2 based on ring-closing metathesis and C(sp)−C(sp 3 ) Sonogashira coupling with a 36.5% overall yield has been described. The ready availability of starting materials and key Wittig olefination, ring-closing metathesis, Lindlar reduction, and C(sp)−C(sp 3 ) coupling makes this strategy applicable for the synthesis of various unbranched polyene-natural products with 1,5,9,n-(Z)-configured double bonds.

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