The first examples of 1,3,2-diazaphospholene-catalyzed imine reduction and conjugate reactions are reported. This approach employs readily synthesized alkoxydiazaphospholene precatalysts that can be handled in open air. Reduction substrates containing Lewis basic functionality, isolated unsaturation, protic functional groups was accomplished. synthetic utility this is demonstrated by the synthesis important antiparkinson medicine rasagiline natural product zingerone.

A convergent diastereo- and enantioselective total synthesis of anticancer antifungal macrocyclic natural product disorazole C1 is reported. The central feature the successful route application catalytic Z-selective cross-metathesis (CM). Specifically, we illustrate that catalyst-controlled stereoselective CM can be performed to afford structurally complex Z-alkenyl–B(pin) as well Z-alkenyl iodide compounds reliably, efficiently, with high selectivity (pin = pinacolato). resulting...

We demonstrate pyridine hydroboration catalyzed by a diazaphospholene hydride precatalyst. Pyridines bearing electron-withdrawing groups in the 3-position are hydroborated efficiently. This system features low catalyst loadings, fast reaction times at ambient temperature, and tolerance of other reducible functionality. Off-cycle products hydrophosphination were also obtained one case from stoichiometric structurally characterized.

The first use of phosphenium cations in asymmetric catalysis is reported. A diazaphosphenium triflate, prepared two or three steps on a multigram scale from commercially available materials, catalyzes the hydroboration hydrosilylation cyclic imines with enantiomeric ratios up to 97:3. Catalyst loadings are as low 0.2 mol %. Twenty-two aryl/heteroaryl pyrrolidines and piperidines were using this method. Imines containing functional groups such thiophenes pyridyl rings that can challenge...

Abstract The first use of diazaphospholenes as chiral catalysts has been demonstrated with enantioselective imine hydroboration. A diazaphospholene prepared in a simple three‐step synthesis from commercial materials shown to achieve the highest enantioselectivity for hydroboration alkyl imines pinacolborane reported date. Enantiomer ratios up 88:12 were obtained low (2 mol %) catalyst loadings. Twenty examples asymmetric reduction employing this main‐group catalysis protocol, including...

Get me a­ Z (olefin): Efficient catalytic cross-metathesis reactions that afford Z-disubstituted allylic silyl or benzyl ethers are reported (see scheme, MAP=monoalkoxide pyrrolide). The approach, in combination with cross-coupling, provides a general entry to otherwise difficult-to-access alkyne-containing olefins.

A one-pot synthesis of alkyl-containing diazabutadienes from primary alkylamine-HCl salts is presented. This avoids halogenated solvents, and the need for a separate free-basing step commercially available or synthesized amine-HCl salts. Since amine HCl are conveniently handled, commonly used as either ligands, precursors heterocycles including N-heterocyclic carbenes diazaphospholenes, this route will be convenience to many researchers in multiple areas catalysis.

A convergent synthesis of the marine natural product (+)-peloruside has been reported. This target assembled through successive application two methyl ketone boron aldol addition reactions to latent C7−C11 dialdehyde synthon. approach afforded a 22-step this product. The influence resident stereocenters on reaction diastereoselection examined in detail.

The synthesis and study of the catalytic activity 1,2,4,3-triazaphospholenes (TAPs) is reported. TAPs represent a more modular scaffold than previously reported diazaphospholenes. TAP halides were shown to catalyze 1,2 hydroboration 19 imines, three α,β unsaturated aldehydes with pinacolborane, including examples that did not undergo by diazaphospholene systems. DFT calculations support mechanism where triazaphospholene cation interacts substrate, distinct from catalyzed hydroborations.

Abstract The first examples of 1,3,2‐diazaphospholene‐catalyzed imine reduction and conjugate reactions are reported. This approach employs readily synthesized alkoxydiazaphospholene precatalysts that can be handled in open air. Reduction substrates containing Lewis basic functionality, isolated unsaturation, protic functional groups was accomplished. synthetic utility this is demonstrated by the synthesis important antiparkinson medicine rasagiline natural product zingerone.

We report herein on the synthesis and catalytic application of a family o-phenylene-bridged bisphosphine ancillary ligands featuring bulky N-heterocyclic phosphine (NHP) donor fragment paired with an adjacent PR2 group (R = alkyl, aryl), whereby incorporation phosphorus into either saturated or unsaturated heterocyclic ring serves as means modulating donicity NHP fragment. Screening these in representative nickel-catalyzed C(sp2)–N cross-coupling test reactions allowed for identification one...

Diazaphospholenes are widely used as hydride transfer catalysts, however their use in radical reactions is a recently emerging area. Here, we show prior stoichiometric cyclizations of aryl iodides mediated by diazaphospholene hydrides made catalytic the combination phenylsilane and alkali metal salts to regenerate hydride. The scope was expanded include bromides, which benefit from visible light irradiation. Twenty one substrates underwent cyclization, including dearomative cyclization....

Abstract The first use of diazaphospholenes as chiral catalysts has been demonstrated with enantioselective imine hydroboration. A diazaphospholene prepared in a simple three‐step synthesis from commercial materials shown to achieve the highest enantioselectivity for hydroboration alkyl imines pinacolborane reported date. Enantiomer ratios up 88:12 were obtained low (2 mol %) catalyst loadings. Twenty examples asymmetric reduction employing this main‐group catalysis protocol, including...

The use of cyclic α,β-unsaturated iminium-ion dienophiles is documented in two highly diastereoselective Diels–Alder (DA) reactions. dienophilic counterion was found to have a significant effect on reactivity.

Polydicyclopentadiene (PDCPD) is a durable, highly cross-linked material that used industrially for the production of automotive body panels among other applications. We recently described novel C-linked, ester-functionalized polydicyclopentadiene (fPDCPD) introduces tunable surface energy and increased Tg, without sacrificing desirable thermal stability parent polymer. In this report, we describe an extensive spectroscopic study aimed at rigorous characterization structure cross-link in our...

Secondary phosphine oxides, which are air and water stable, purifiable by chromatography generate phosphenium or phosphorus hydride catalysts <italic>in situ</italic>.

Phosphorus‐sp 3 or ‐sp 2 carbon bonds are readily formed by the reaction of bis‐diazaphospholenes with several classes electrophiles. These reactions result in cleavage phosphorus–phosphorus bond and formation functionalized diazaphospholenes. The proceed rapidly, without catalysis. Experimental evidence aryl alkyl halides suggests intermediacy radicals some cases, however other either radical polar mechanisms may be operative for certain substrates, a dependence on conditions. In three...

We report here that addition of stoichiometric amounts alcohols or water to mixtures imines and pinacolborane promote reduction reactions. The reactions several were examined, revealing alkyl reduced, while aniline derived not effectively reduced. use binol as an additive resulted in modest enantioinduction, however other chiral additives screened gave negligible enantioinduction. While the described herein are competitive conversion with established imine technologies, this work reveals...

Gib mir ein­ Z(-Olefin): Effiziente katalytische Kreuzmetathesen ergeben Z-disubstituierte allylische Silyl- oder Benzylether (siehe Schema, MAP=Monoalkoxidpyrrolid). In Kombination mit einer katalytischen Kreuzkupplung dient der Ansatz als eine allgemeine Synthesemethode für ansonsten schwer zugängliche Z-Olefine Alkingruppen.

The first reported neutral boron(III) adducts of bis(amino)cyclopropenylidene carbenes (BAC carbenes) have been synthesized, structurally characterized, and applied in homogeneous reaction chemistry. These air-stable prepared by the combination a BAC carbene lithium tetrafluoroborate adduct with borane dimethyl sulfide, boron trifluoride etherate, or dicyclohexylborane. A borenium cation derived situ from dicyclohexylborane catalytically reduces unhindered benzyl ketimines, class substrate...

Upon treatment with sulfur hexafluoride, alkali metal diphenyl or dicyclohexyl phosphides are oxidized within seconds to tetraphenyl tetracyclohexyl diphosphines. This is a rare example of reactivity hexafluoride at ambient temperature.

Abstract Diazaphospholenes are widely used as hydride transfer catalysts, however their use in radical reactions is a recently emerging area. Here, we show prior stoichiometric cyclizations of aryl iodides mediated by diazaphospholene hydrides made catalytic the combination phenylsilane and alkali metal salts to regenerate hydride. The scope was expanded include bromides, which benefit from visible light irradiation. Twenty one substrates underwent cyclization, including dearomative...

Borenium-catalyzed hydrogenations of an imine made from a benzylamine are enabled by steric interplay between cyclohexylborane and BAC carbene: both necessary for efficient reactivity.