Iridium‐Catalyzed H/D Exchange at Vinyl Groups without Olefin Isomerization

Abstract

Making the switch: The title reaction represents a rare example of olefinic CH activation without olefin isomerization. The conditions are sufficiently mild so that functional groups such as ketones, esters, nitriles, amines, sulfides, and alcohols are tolerated. This selectivity is demonstrated by deuterium labeling of several complex molecules.

Heteroatoms moving protons: Synthetic and mechanistic studies of bifunctional organometallic catalysis

“…Those which perform H/D exchange at alkene C-H bonds usually do so with competing and poorly controlled alkene isomerization [65][66][67][68][69][70][71]. A recent exception is an iridium catalyst which does not isomerize alkenes [71]. None of these catalysts appear to act selectively at allylic positions as would be predicted by Fig.…”

“…Of the many catalysts for H/D exchange, most are effective on arene and alkane C-H bonds [63,64]. Those which perform H/D exchange at alkene C-H bonds usually do so with competing and poorly controlled alkene isomerization [65][66][67][68][69][70][71]. A recent exception is an iridium catalyst which does not isomerize alkenes [71].…”

H/D Exchange on Silica-Grafted Tantalum(V) Imido Amido [(≡SiO)2Ta(V)(NH)(NH2)] Synthesized from Either Ammonia or Dinitrogen: IR and DFT Evidence for Heterolytic Splitting of D2

“…A classical way to start probing the reactivity of a new complex is the investigation of its H/D exchange reactions: such a longstanding approach in the study of C-H and H-H bond activation and reaction mechanisms [17][18][19][20][21][22][23][24] is being extended, given the renewed interest in catalytic C-H activation [25][26][27] and novel applications of deuterium tags in biocatalysis [28][29][30][31] and analytical chemistry [32,33], leading to the current renaissance of the topic [34,35].…”

Ruthenium(II)biscarboxylate‐Catalyzed Hydrogen‐Isotope Exchange by Alkene C−H Activation

“…While reports on the H/D exchange at aromatic C(sp 2 )−H bonds have been described, effective strategies for the chemo‐selective deuteration of alkenes continue to be scarce (Scheme ). In this context, inspired by studies from Bergman and Tilley, Hartwig described an iridium pincer complex, that allowed for the selective H/D scrambling at alkenyl moieties without isomerization, exploiting C 6 D 6 as the deuterium source . In contrast, Grotjahn showed that allylic deuteration of alkenes was accomplished by a bifunctional imidazolylphosphine,, whereas Oro used NHC‐supported rhodium(III) hydride catalyst for the selective β‐deuteration of styrenes ,.…”