How to Facilitate Diastereoselective Nucleophilic Addition ─ Part 1

Diastereoselective nucleophilic addition (AN) is not accomplished easily; however, the use of an unconventional reagent may pave the way for a successful end product.


Diastereomers (aka diastereoisomers) are constitutionally identical molecules non-mirror images of each other, can have different biological activities, potencies or toxicities, and occur when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the corresponding stereocenters and are not mirror images of each other.

An AN reaction is an addition reaction where an organic compound with an electrophilic double/triple bond reacts with a nucleophile s.t. the double/triple bond undergoes a cleavage.

An allyl group is a nucleophile which can add to an α-oxy carbonyl (C=O) compound in two ways; either opposite to the α-O (making syn-adduct) or same side as the α-O (producing anti-adduct). The high chelation tendency of the α-oxy group typically yields the syn-adduct.

Use of a cage-like allyl reagent has caused allylation to be anti-selective in a novel method.



Click/tap to enlarge the image

Dumbfounded by diastereomers❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com❗

References:

(1)    Tsutsui, Y.; Shiga, K.; Konishi, A.; Yasuda, M. Non-Chelation Control in Allylations of α-Oxy Ketones Using Group-14 Allylatranes. Nature Communications 2026, 17 (1). https://doi.org/10.1038/s41467-026-69732-2.

(2)    Nucleophilic addition. Wikipedia. https://en.wikipedia.org/wiki/Nucleophilic_addition.

(3)    Diastereomer. Wikipedia. https://en.wikipedia.org/wiki/Diastereomer.

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