Dirhodium(II)/DPPM Catalyzed 1,2-Hydrosilylation of Conjugated Dienes with Tertiary Silanes

Organic Letters, Год журнала: 2024, Номер 26(11), С. 2287 - 2291

Опубликована: Март 8, 2024

A simple and efficient Rh2(OAc)4/DPPM (bis(diphenylphosphanyl)methane) catalyzed regioselective 1,2-anti-Markovnikov hydrosilylation of conjugated dienes with various tertiary silanes gave homoallylic in acetonitrile, which tolerate broad functional groups. Control experiments proved that no π-allyl transition metal intermediates were involved this hydrosilylation. Dirhodium hydride species was observed hydrosilylation, suggesting a direct insertion the terminal double bond into Rh–H is reaction.

Язык: Английский

---

Cobalt‐Catalyzed Enantioselective Alkenylation of Aldehydes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(33)

Опубликована: Май 31, 2024

Catalytic enantioselective alkenylation of aldehydes with easily accessible alkenyl halides promoted by a chiral cobalt complex derived from newly developed tridentate bisoxazolinephosphine is presented. Such processes represent an unprecedented reaction pathway for catalysis and general approach that enable rapid construction highly diversified enantioenriched allylic alcohols containing 1,1-, 1,2-disubstituted trisubstituted alkene as well axial stereogenicity in up to 99 % yield : 1 er without the need preformation alkenyl-metal reagents. DFT calculations revealed origin enantioselectivity.

Язык: Английский

---

Copper-catalyzed intermolecular Regio- and Enantioselective Hydrosilylation of Alkenes with Prochiral Silanes

Nature Communications, Год журнала: 2025, Номер 16(1)

Опубликована: Янв. 3, 2025

This study presents a copper-catalyzed, substrate-controlled regio- and enantioselective intermolecular hydrosilylation method capable of accommodating broad scope alkenes prochiral silanes. The approach offers an efficient versatile pathway to generate enantioenriched linear branched alkyl-substituted Si-stereogenic Key features this reaction include mild conditions, simple catalytic systems, compatibility with diverse substrates, high yields enantioselectivities. While methods create chiral carbon centers stereochemically defined silicon have been developed, the ability both simultaneously would be value. Here authors present substratecontrolled

Язык: Английский

---

Catalytic Asymmetric Dehydrogenative Si–H/X–H Coupling toward Si-Stereogenic Silanes

Accounts of Chemical Research, Год журнала: 2025, Номер unknown

Опубликована: Янв. 22, 2025

ConspectusChiral organosilicon compounds bearing a Si-stereogenic center have attracted increasing attention in various scientific communities and appear to be topic of high current relevance modern organic chemistry, given their versatile utility as chiral building blocks, reagents, auxiliaries, catalysts. Historically, access these non-natural silanes mainly relies on resolution, whereas asymmetric synthetic methods dramatically lagged compared carbon counterparts. Over the past two decades, transition-metal-catalyzed desymmetrization prochiral organosilanes has emerged an effective tool for synthesis enantioenriched silanes. Despite progress, catalytic reactions usually suffer from limited substrate scope, poor functional-group tolerance, low enantioselectivity. The growing demand with structural diversity continued drive development new practical assembly molecules.Five years ago, our research group embarked project aimed at developing general approach that can unlock functionalized efficiency. This Account describes laboratory's endeavor exploration dehydrogenative Si–H/X–H coupling toward features (1) readily accessible dihydrosilane starting materials; (2) diverse X–H (X═C, N, O, etc.) partners; (3) platform transformable monohydrosilane products; (4) efficiency atomic economy.At initial stage research, biaryl was selected model conduct enantioselective intramolecular C–H/Si–H reaction. Rh/Josiphos system found early this process, while final enantiocontrol elusive. Mechanistic studies indicated rhodium silyl dihydride complex is resting state cycle, which may undergo racemization center. Enlightened by mechanistic investigations, strategies, tandem alkene hydrosilylation strategy bulky alkene-assisted strategy, were adopted avoid racemization, delivering corresponding 9-silafluorenes excellent yields enantioselectivities. Further C(sp2)–H or C(sp3)–H silylation gave series five-, six- seven-membered heterocycles Next, we extended reaction intermolecular version, realizing Si–H/C–H, Si–H/O–H, Si–H/N–H variety acyclic monohydrosilanes, ethers, siloxanes, silanols, silazanes. We also presented endeavors apply resulting compounds, including further derivatization, polymerization, chiroptical property successfully introduced Si-stereocenters into bioactive molecules, polymers, materials. Lastly, based understanding metal species, developed type ligand applied enable atroposelective anticipate methodology, insights, studies, will not only inspire chemistry but contribute creation novel molecules medicinal materials science.

Язык: Английский

---

Enantioconvergent construction of stereogenic silicon via Lewis base-catalyzed dynamic kinetic silyletherification of racemic chlorosilanes

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Авг. 14, 2023

Organosilanes possessing an enantioenriched stereogenic silicon center are important in many branches of chemistry, yet they remain challenging to synthesize a practical and scalable way. Here we report dynamic kinetic silyletherification process racemic chlorosilanes with (S)-lactates using 4-aminopyridine as Lewis base catalyst. This enantioconvergent approach asymmetrically constructs the different manner from traditional resolution or desymmetrization. A range silylethers have been prepared high diastereoselectivity on up 10 g-scale, allowing synthesis diverse organosilane analogs.

Язык: Английский

---

Chemodivergent Tandem Hydroalkylation and Hydroalkenoxylation of Conjugated Enynes

ACS Catalysis, Год журнала: 2024, Номер 14(13), С. 9742 - 9751

Опубликована: Июнь 14, 2024

Due to the instability and weak O-nucleophilicity of enol, carbonyl compounds prefer function as C-nucleophiles instead O-nucleophiles in extensively studied transition metal-catalyzed hydrofunctionalizations unsaturated bonds. The corresponding hydroalkenoxylation reaction has thus long been unexplored. Here, we describe a chemodivergent protocol for challenging reactions. Dictated by Pd catalyst bearing different ligands, both 5-exo-trig 6-endo-trig processes are demonstrated be feasible between 1,3-enynes ketoesters, polysubstituted hydrofurans hydropyrans achieved good yields excellent chemoselectivities. In addition, enantioselective is also explored under an Rh moderate efficiency but with high stereoselectivities. Mechanistic studies corroborate designed tandem hydroalkylation uncover that ligand-to-ligand hydrogen transfer process might involved turnover-limiting step hydroalkenoxylation.

Язык: Английский

---

Enantioselective Hydrosilylation of β,β‐Disubstituted Enamides to Construct α‐Aminosilanes with Vicinal Stereocenters

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(1)

Опубликована: Ноя. 8, 2022

Despite the advances in area of catalytic alkene hydrosilylation, enantioselective hydrosilylation alkenes bearing a heteroatom substituent is scarce. Here we report rhodium-catalyzed β,β-disubstituted enamides to directly afford valuable α-aminosilanes highly regio-, diastereo-, and manner. Stereodivergent synthesis could be achieved by regulating substrate geometry ligand configuration generate all possible stereoisomers high enantio-purity.

Язык: Английский

---

Ligand-controlled regiodivergence in cobalt-catalyzed hydrosilylation of isoprene

Organic Chemistry Frontiers, Год журнала: 2023, Номер 10(9), С. 2204 - 2210

Опубликована: Янв. 1, 2023

An atom-economical, regiodivergent hydrosilylation reaction of isoprene was developed using an Earth-abundant cobalt catalyst through variation ligands.

Язык: Английский

---

Asymmetric formal sp2-hydrocarbonations of dienes and alkynes via palladium hydride catalysis

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Окт. 9, 2023

Abstract Transition metal-catalyzed asymmetric hydrofunctionalizations of unsaturated bonds via π-ƞ 3 substitution have emerged as a reliable method to construct stereogenic centers, and mainly rely on the use heteroatom-based or carbon nucleophiles bearing acidic C-H bonds. In comparison, sp 2 are generally not under consideration because enormous challenges in cleaving corresponding inert Here, we report protocol achieve formal hydrocarbonations, including hydroalkenylation, hydroallenylation hydroketenimination both 1,3-dienes alkynes hydroalkylation Wittig reaction cascade. A series unachievable motifs hydrofunctionalizations, such di-, tri- tetra-substituted alkenes, allenes, tri-substituted ketenimines allyl skeletons all facilely constructed high regio-, diastereo- enantioselectivities with this cascade design. Stereodivergent synthesis four stereoisomers 1,4-diene stereocenter Z/E-controllable olefin unit highlights power present protocol. An interesting mechanistic feature is revealed that alkyne actually undergoes hydrocarbonation formation conjugated diene intermediate, different from conventional viewpoint hydrofunctionalization only involves allene species.

Язык: Английский

---

Organocatalytic asymmetric synthesis of Si-stereogenic silacycles

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Июль 11, 2024

A strong and confined Brønsted acid catalyzed enantioselective cyclization of bis(methallyl)silanes provides enantioenriched Si-stereogenic silacycles. High enantioselectivities up to 96.5:3.5 er were obtained for a range bis(methallyl)silanes. NMR ESI-MS studies reveal that the formation covalent adduct irreversibly inhibits turnover. Remarkably, we found acetic as an additive promotes collapse this adduct, enabling full Experimental investigation density functional theory (DFT) calculations conducted elucidate origin phenomenon observed enantioselectivity.

Язык: Английский

---