Sequential Deprotonation–Alkylation of Binaphthyloxy-Substituted Phosphonochalcogenoates: Chiral Tri- and Tetrasubstituted Carbon Centers Adjacent to a Phosphorus Atom

Maekawa, Yuuki; Maruyama, Toshifumi; Murai, Toshiaki

doi:10.1021/acs.orglett.6b02578

Cited by 13 publications

(13 citation statements)

References 74 publications

(19 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Organic & Biomolecular Chemistry in diastereoselective sequential deprotonation-alkylation reaction leading to new organophosphorus compounds with triand tetrasubstituted carbon centers adjacent to the phosphorus atom, 49 and 51, respectively (Schemes 17 and 18). 72 In the case of phosphonoselenoates 48, the deprotonation proceeded smoothly with LDA at −70 °C in THF and subsequent addition of the appropriate halides to the in situ generated carbanion resulted in the formation of desired trisubstituted alkylated products 49 with good yields (up to 89%) and high diastereoselectivities (dr up to 5 : 95) (Scheme 17). In the case of products 49f and 49h, simple recrystallization of the crude product resulted in an improvement of the original diastereoselectivity.…”

Section: Reviewmentioning

confidence: 99%

“…Due to the presence of BINOL unit in each case, the diastereomers formed were easily discriminated by means of 31 P NMR. 72 The absolute configuration of the new carbon centers was unambiguously assigned by means of X-ray analysis in the case of products 49a, 49b and 49f (Scheme 17). The authors postulated that the BINOL part exerts a strong influence on the stereochemical fate of the carbon atom connected to the phosphorus.…”

Section: Reviewmentioning

confidence: 99%

See 1 more Smart Citation

Asymmetric synthesis of organophosphorus compounds using H–P reagents derived from chiral alcohols

Gbubele

Olszewski

2021

Org. Biomol. Chem.

View full text Add to dashboard Cite

show abstract

Section: Reviewmentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

Asymmetric synthesis of organophosphorus compounds using H–P reagents derived from chiral alcohols

Gbubele

Olszewski

2021

Org. Biomol. Chem.

View full text Add to dashboard Cite

show abstract

“…To rule out the possibility of a lithiated phosphoramide serving as the base or an anionic intermediate, HMPA isotopomer HMPA-d18 was subjected under the standard lithiation conditions with chromane 29. 85,86 Under these conditions, only protic isobutane (58) could be detected by 1 H, and 13 C NMR spectroscopy i.e., no deuterium exchange (Figure 8 and S18). This result strongly suggests that HMPA is coordinating the Li + cation and not serving as a proton shuttle.…”

Section: Nmr Investigations Of the Organolithium Aggregate Structure:...mentioning

confidence: 99%

Breaking the tert-Butyllithium Contact Ion Pair: A Gateway to Alternate Selectivity in Lithiation Reactions

Crockett

Piña

Nguyen

et al. 2022

Preprint

View full text Add to dashboard Cite

The selective functionalization of saturated oxygen heterocycles at positions remote to the embedded heteroatoms remains an outstanding challenge in organic synthesis. Although many methods exist for the undirected replacement of C–H bonds with heteroatomic subunits the number of site selective C–H functionalization reactions for the introduction of carbon-carbon bonds pales in comparison. This paper describes the initial stages of a long-term program aimed at elucidating how organolithium reagents can be re-engineered to selectively deprotonate and functionalize saturated heterocycles at new locations. Through rigorous NMR spectroscopic investigations, it was determined for the first time that the addition of Lewis basic phosphoramides can shift the equilibrium of strong organolithium bases, such as t-BuLi, to include the triple ion pair (t-Bu–Li–t-Bu) / L4Li which serves as a reservoir for the highly reactive separated ion pair t-Bu / L4Li . Because the Li-atom’s valences are saturated the Lewis acidity is significantly decreased and the basicity is maximized which allowed for the typical directing effects within oxygen heterocycles to be overridden and for remote sp3-CH bonds to be deprotonated. In certain cases, this enabled the removal of stronger C–H bonds in the presence of weaker C–H bonds. Furthermore, these newly accessed lithium aggregation states were leveraged to develop a simple γ-lithiation and capture protocol (lithium nucleophilic coupling – “LiNC”) of chromane heterocycles with a variety of alkyl halide electrophiles in good yields.

show abstract

“…The stereochemistry on a phosphorus atom has not received much attention, despite the fact that the introduction of at least three different substituents to the phosphorus atom gives rise to the stereogenic center on the phosphorus atom. During the course of our studies on main group chemistry [39,40], we have intensively studied the synthesis and applications studies on main group chemistry [39,40], we have intensively studied the synthesis and applications of organophosphorus compounds with a binaphthyl group [41][42][43][44][45] and recently reported that the deprotonation and alkylation of phosphonoselenoates and phosphonates with a binaphthyl group creates stereogenic secondary and tertiary carbon centers adjacent to the phosphorus atom with high diastereoselectivity (Scheme 1a,b) [46]. The resulting products are potentially available as precursors of primary phosphines since phosphorus-oxygen bonds are readily reduced to P-H bonds.…”

Section: Introductionmentioning

confidence: 99%

Primary Phosphines and Phosphine Oxides with a Stereogenic Carbon Center Adjacent to the Phosphorus Atom: Synthesis and Anti-Markovnikov Radical Addition to Alkenes

et al. 2021

Self Cite

View full text Add to dashboard Cite

Organophosphorus compounds with stereogenic phosphorus and carbon atoms have received increasing attention. In this regards, primary phosphines with a stereogenic carbon atom adjacent to the phosphorus atom were synthesized by the reduction in phosphonates and phosphonoselenoates with a binaphthyl group. Their oxidized products, i.e., phosphine oxides with a stereogenic tetrasubstituted carbon atom, were found to undergo BEt3-mediated radical addition to cyclohexene to give P-stereogenic secondary phosphine oxides with a diastereoselectivity of 91:9. The products were characterized by ordinary analytical methods, such as Fourier transform infrared spectroscopy; 1H, 13C, and 31P NMR spectroscopies; and mass spectroscopy. Computational studies on the phosphorus-centered radical species and the obtained product implied that the thermodynamically stable radical and the adduct may be formed as a major diastereomer. The radical addition to a range of alkenes took place in an anti-Markovnikov fashion to give P-stereogenic secondary phosphine oxides. A variety of functional groups in the alkenes were tolerated under the reaction conditions to afford secondary phosphine oxides in moderate yields. Primary phosphines with an alkenyl group, which were generated in situ, underwent intramolecular cyclization to give five- and six-membered cyclic phosphines in high yields after protection by BH3.

show abstract

Sequential Deprotonation–Alkylation of Binaphthyloxy-Substituted Phosphonochalcogenoates: Chiral Tri- and Tetrasubstituted Carbon Centers Adjacent to a Phosphorus Atom

Abstract: Sequential deprotonation and alkylation of 1,1'-binaphthyloxy-substituted phosphonoselenoates and phosphonates resulted in the diastereoselective formation of chiral tri- and tetrasubstituted carbon centers adjacent to a phosphorus atom.

Cited by 13 publications

References 74 publications

Asymmetric synthesis of organophosphorus compounds using H–P reagents derived from chiral alcohols

Asymmetric synthesis of organophosphorus compounds using H–P reagents derived from chiral alcohols

Breaking the tert-Butyllithium Contact Ion Pair: A Gateway to Alternate Selectivity in Lithiation Reactions

Primary Phosphines and Phosphine Oxides with a Stereogenic Carbon Center Adjacent to the Phosphorus Atom: Synthesis and Anti-Markovnikov Radical Addition to Alkenes

Contact Info

Product

Resources

About