Are Organozirconium Reagents Applicable in Current Organic Synthesis?

Abstract

The search for mild, user-friendly, easily accessible, and robust organometallic reagents is an important feature of organometallic chemistry. Ideally, new methodologies employing organometallics should be developed with respect to practical applications in syntheses of target compounds. In this short review, we investigate if organozirconium reagents can fulfill these criteria. Organozirconium compounds are typically generated via in situ hydrozirconation of alkenes or alkynes with the Schwartz reagent. Alkyl and alkenylzirconium reagents have proven to be convenient in conjugate additions, allylic substitutions, cross-coupling reactions, and additions to carbonyls or imines. Furthermore, the Schwartz reagent itself is a useful reducing agent for polar functional groups.1 Introduction2 Synthesis and Generation of the Schwartz Reagent3 Structure and Properties of Cp2Zr(H)Cl4 Reactivity of Organozirconium Reagents4.1 Asymmetric Conjugate Addition4.2 Asymmetric Allylic Alkylations4.3 Desymmetrization Reactions4.4 Cross-Coupling Reactions4.5 1,2-Additions5 Conclusions

Zirconium oxo clusters as discrete molecular catalysts for the direct amide bond formation

“…1,2 In addition, organozirconium species, frequently generated by hydrozirconation reactions, have a highly polarized Zr–C bond, and their ability to undergo a transmetalation step has been leveraged for the total synthesis of many complex molecules. 3–8 Yet, Zr( iv ) strong Lewis acidity and the characteristic oxophilicity of group (IV) metals still pose a challenge for its broader use, due to the regular need for inert and dry conditions in order to avoid Zr catalyst decomposition, and secure good overall efficiency for the desired transformation. 9 Thus, more robust zirconium catalysts with tunable reactivity bear the potential to boost their synthetic utility, which is an important goal in sustainable chemistry, considering the greater abundance of zirconium compared to many other transition metals commonly employed in catalysis.…”

Expanding Zirconocene Hydride Catalysis: In Situ Generation and Turnover of ZrH Catalysts Enabling Catalytic Carbonyl Reductions

“…7,8 Upon hydrozirconation, the resulting organozirconium reagents participate in a wealth of organic transformations through transmetalation or electrophilic trapping. 9 Furthermore, the attenuated nucleophilicity of organozirconium species renders these complexes comparatively mild and functional group tolerant. While Schwartz's reagent is commercially available and is frequently used to achieve a variety of fundamental synthetic transformations in organic synthesis, this reagent has an exceptionally short shelf life due to air, moisture, and light sensitivity.…”

Enantioselective Decarboxylative C(sp3)-C(sp3) Cross-Coupling of Aliphatic Acids with gem-Borazirconocene Alkanes

“…This versatile organometallic specie demonstrates exceptional functional group tolerance, unique photochemical reactivity, and the capacity to facilitate remote C-H functionalization through their intriguing "chain-walking" ability. Notably, alkylzirconocenes can be readily prepared from abundant and readily available feedstock chemicals, such as alkenes [60][61][62] . The confluence of these desirable reactivity features and their synthetic accessibility renders alkylzirconocenes highly attractive synthetic intermediates for the efficient assembly of complex molecular architectures.…”