Syntheses of a new type of chiral phosphines from glucose

Methyl 3-deoxy-3-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (1) and methyl 2-deoxy-2-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (2) were prepared from methyl 2,3-anhydro-4,6-O-benzylidene-O-D-mannopyranoside and methyl 2,3-anhydro-4,6-O-benzylidene-alpha-D-allopyranoside, respectively, via regioselective and stereospecific ring-opening reactions in high yields. Compounds 1 and 2 were oxidized to give the corresponding phosphine oxides (3 and 4).

Chiral Phosphine Ligands Derived from Sugars 4.Crystal Structure of Methyl 4,6-O-Benzylidene-3-Deoxy-3-(Diphenylphosphino)-α-D-Altropyranoside (3-MBPA)

The crystal structure of the title compound 3--MBPA, C26H27O5P (Mr.= 450. 44 ). has been determined by single--crystal X-ray diffraction. The crystal ismonoclinic with space group P21, a= 9. 294(l), b= 7. 999(1), c= 15. 925(2) A,β=96. 17(5)°, V= 1176. 9 A 3, Dc=l. 271 g/cm3, F(000)=476, μ=12. 99 cm-1,Z=', Z=2, and final R = 0. 045 and Ru= 0. 057 for 1882 reflections (I≥3a(I) ). Structureanalysis revealed that the pyranose and 4, 6--O--benzylidene ring of the title compoundadopt a distorted chair conformation and the diphenylphosphino, OH and OMe groupsare in pseudo--axial position.

Chiral Phosphine Ligands Derived from Sugars8. Crystal and Molecular Structure of Diphenyl (methyl 4', 6'-O-benzylidene-2'-deoxy-α-D-altropyranoside-2-)phosphine Oxide

The crystal structure of the title compound, C26H27O6P, has been determined by single--crystal X-ray diffraction. The crystal is monoclinic with space groupP21, a=16. 193(l), b=5. 804(1), c=12. 512(2) A, β=93. 187(5)°, V=1174. 13A3, Dc=1. 319 g/cm3, F(000) =492, μ= 13. 52 cm-1, Z= 2, and final R= 0. 042and Rw= 0. 040 for 2349 reflections (I≥3σ(I)). Structure analysis revealed that thepyranose and 4, 6-O-benzylidene ring of the title compound adopts a distorted chair conformation.

Chiral Phosphine Ligands Derived fro m Sugars .14 . Crystal Structure of Diphenyl( m ethyl4’,6’-O-benzylidene-3’-deoxy-α- D-altropyranoside-3-)phosphine Oxide

The crystal structure of the title compound, C 26 H 27 O 6P, has been determined by single crystal X ray diffraction analysis. The crystal is orthorhombic with space group P2 12 12 1, a=6.154(4), b=17.199(8), c=22.180(3) , V=2347.6 3, D c=1.32 g/cm 3, F(000)=984, μ=1.5 cm -1 , Z =4, and final R =0.075 and R w =0.080 for 1417 reflections (I≥3σ(I)) . The X ray diffraction analysis revealed that the structure of the title compound s similar to that of its parent phosphine and the pyranose and 4, 6 O benzylidene rings remain distorted chair conformations.

Enantioselective Allylic Amination of Morita-Baylis-Hillman Acetates Catalyzed by Chiral Thiourea-Phosphine

The enantioselective allylic amination of Morita-Baylis-Hillman acetates catalyzed by chiral cyclohexane-based thiourea-phosphine catalysts was investigated. In the presence of 20 mol% rosin-derived thiourea-phosphine 3j, the chiral amines were obtained in up to 88% yield and up to 85% ee.

Highly efficient synthesis of chiralβ-amino phosphine derivatives via direct asymmetric reductive amination with ammonium salts and H_(2)

A highly efficient and enantioselective method for the asymmetric reductive amination ofβ-keto phosphine de-rivatives was disclosed,and the correspondingβ-amino phosphine oxides could be obtained in high yields(up to 97%yield)and excellent enantioselectivities(up to 97%ee).Moreover,the reaction worked well on a gram scale,indicating that our protocol has potential applications in the synthesis of chiral ligands and organocatalysts.

Enantioselective[3 t 2]cycloadditions of terminal allenoates withβ-sulfonyl-α,β-unsaturated ketones

A highly efficient and mild method for[3 t 2]cycloaddition ofβ-sulfonyl-α,β-unsaturated ketones with terminal allenoates was well-explored and developed.The reactions were successfully performed by applying multifunctional chiral phosphine P6 which was screened from eight chiral phosphorus reagents to finally result in a variety of enantioenriched sulfone-substituted cyclopentenes with two chiral centers(up to 81%yield with 94%ee).Moreover,2.5 mol%catalytic equivalents were proved to be feasible when this reaction was performed on a 10 mmol scale.