New Applications of Polyfunctional Organometallic Compounds in Organic Synthesis

Abstract

In the second half of the twentieth century much effort was invested in the preparation of highly reactive polar organometallic reagents. The high reactivity of these reagents precluded the presence of many functional groups and often good chemoselectivities and stereoselectivities could only by achieved by transmetalation reactions. The synthesis of increasingly complex target molecules and the desire to avoid tedious protection–deprotection steps has led inevitably to the use of functionalized organometallic reagents in retrosynthesis. In the last fifteen years, the generation of organic derivatives of numerous metals and metalloids (Li, Mg, B, Zn, Sn) was investigated. In this review the most important preparations and applications of organometallic reagents in organic synthesis will be covered, with particular emphasis on organozinc reagents.

Iron-Catalyzed Chemoselective Cross-Coupling of Primary and Secondary Alkyl Halides with Arylzinc Reagents

“…3 However, a drawback of the iron-catalyzed cross-coupling reaction of haloalkanes is that the nucleophilic partner has been limited largely to organomagnesium reagents, 7 in which electrophilic substituents can survive only at low temperatures. 8 Here, we report an iron-catalyzed cross-coupling of primary or secondary alkyl halides with arylzinc reagents, where the mild reactivity of the zinc reagents much improves the functional group tolerance and the synthetic practicability of the cross-coupling reaction.…”

Zinc: Organometallic ChemistryBased in part on the article Zinc: Organometallic Chemistry by Gerard Parkin which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

“…163 Interestingly, the octameric aggregation of the last compound is not retained in benzene solution where hexamers are observed. Finally, a wurtzite-like structure has been found for the decamer [EtZn(SEt)] 10 . 159 The pentamer [MeZn(S-t-Bu)] 5 readily reacts with nitrogenous bases like pyridine and 1,3,5-trimethylhexahydro-1,3,5-triazine to form stable adducts of the dimeric species, 164 which, in contrast to the parent oligomers, present a good solubility in organic solvents.…”

Polymer-supported N-heterocyclic carbene–rhodium complex catalyst for the addition of arylboronic acids to aldehydes

“…The addition of organometallic reagents to aldehydes has been one of the general methods for the synthesis of diarylmethanols. Of these reagents, organolithium and organomagnesium compounds are most frequently used for this purpose, but tolerate only a few electrophilic groups on themselves [4][5][6][7][8][9][10][11]. Examples of using other functionalized organometallic species [12][13][14][15][16][17][18][19] such as organocopper, organochromium, organotin, especially organozinc, have been described.…”