Development of Neighboring Electrophilic Activation of Active Center in Catalytic Reactions via Organometallic Intermediates

Abstract

Strategies for electrophilic activation by neighboring atoms should contribute to the development of novel catalytic performance in organic reactions. Neighboring electron-withdrawing Lewis acidic atoms can change the character of molecular catalysts, which might be more electrophilic toward inactive electron-rich molecules. In this context, the development of carbene intermediates, diborylmethane derivatives, and multinuclear catalysts has realized efficient transformations. The use of cyclopropenes can generate electrophilic carbenoid intermediates in the presence of a Ag-catalyst, the reaction of which with an organozinc reagent gives allylzinc intermediates. The subsequent allylation reaction of other electrophiles takes place in situ as a 3-components coupling reaction. The novel reactivity of diborylmethane derivatives shows the generation of borate intermediates under ambient conditions, which can take part in the SuzukiMiyaura cross-coupling reaction. The mono-coupling reaction occurs exclusively without di-coupling reaction to give alkylboronates. The stereoselective synthesis of tetrasubstituted alkenylboronates was successful via the deprotonation of diborylalkanes, subsequent nucleophilic attack to ketones, and syn-elimination. The development of multinuclear catalysts using phosphorous ligands bearing protic moieties has realized efficient stereoselective 1,4-addition reaction of organozinc and organoaluminum reagents, where the creation of chiral quaternary stereogenic centers using acyclic enones is notable.

Structural Characterization and Unique Catalytic Performance of Silyl-Group-Substituted Geminal Dichromiomethane Complexes Stabilized with a Diamine Ligand

“…Bench-stable gem -dimetalloalkanes (R 2 CM 1 M 2 ), possessing two metal atoms on the same carbon, are useful synthons equivalent to dianions . A classic example is the Tebbe reagent (Ti–CH 2 –Al), which is a widely used organo­metallic reagent for methylenation of carbonyl compounds .…”

Photo-activated CO-release in the amino tungsten Fischer carbene complex, [(CO)5WC(NC4H8)Me], picosecond time resolved infrared spectroscopy, time-dependent density functional theory, and an antimicrobial study

“…Fischer carbene complexes have been used widely as reagents in various organic transformations, and in organometallic synthesis, using both thermal and photochemical approaches [1][2][3][4][5]. Fischer carbene complexes of group 6 metals have been shown to react under photochemical conditions with imines, alkenes, aldehydes or alcohols producing a wide variety of useful compounds including β-lactams, βlactones, cyclobutanones, or amino esters [6][7][8][9].…”

Cyclization of 1,n-Enynes Initiated by the Addition Reaction ofgem-Dichromiomethane Reagents to Alkynes

“…Bench-stable gem -dimetalloalkanes (R 2 CM 1 M 2 ) possessing two metal atoms on the same carbon are classical but still important reagents in organic synthesis , Thanks to their mild reactivity, functional groups on the gem -dichromiomethane species were well-tolerated to convert various aldehydes into synthetically useful alkenyl iodides, silanes, and boranes with high regioselectivity .…”