C p - PowerPoint PPT Presentation

日本化学会第8 9 春季年会 １F 1 1 2 非対称ジオール類のラクトン化反応における位置選択性と カチオン性C p R u ( P N ) 錯体の構造との相関 * ( 東工大院理工) 伊藤 正人○椎橋 彬・碇屋 隆雄

Cp*Ru(PN) CATALYSTS WITH A BIFUNCTION BASED ON METAL/NH BOND Possible transition state R 1 R 1 Ru Ru R Ar 2 P Ar 2 P R 2 H H H R' OR 2 N N O Ru H H R R N O [Ru] [Ru]-H 2 H 16e amide complex 18e amine hydride complex Org. Biomol. Chem. 2006 , 4 , 393. Lactonization of α,ω -diols OH O H [Ru] O H [Ru]-H 2 HO H R R R R OH O O O OH OH R R R R [Ru]-H 2 [Ru] OH O H Org. Lett. 2007 , 9 , 1821.

THIS WORK: REGIOSELECTIVE LACTONIZATION OF 2-BENZYL-1,4-BUTANEDIOL O CpRu(PN) 2 2 2 KO t -Bu 1 OH 1 1 O + O Ru 4 OH 4 4 acetone R 2 P Cl R R NHR R O R A B R R R CpRu(PN) O O O O 2 1 O O 4 O O R CH 3 O O O O CH 3 O O OCH 3 O O Hinokinin O Isostegane O O O AcO O O OCH 3 CH 3 O OCH 3 CH 3 O OCH 3 OCH 3 Isodeoxypodophyllotoxyn Podophizol acetate

STRUCTURAL EFFECT OF PN LIGAND ON REGIOSELECTIVITY O [Ru] 1 1 1 OH KO t -Bu O + O OH 4 acetone 4 4 30 °C, 1 h O diol:[Ru]:KO t -Bu = 100:1:1 A B >99% yield [diol] = 0.5 M H Ph 2 P NHR Ph 2 P N Ph 2 P NH 2 Ph 2 P NH 2 R = H 77:23 R Me 82:18 R = Ph 81:19 80:20 81:19 Bn 83:17 Bn 76:24 Ru R 2 P Cl R 2 P NH 2 Ph 2 P NH 2 Ph 2 P NH 2 NHR R = o -Tol 88:12 [Ru] Cy 96:4 90:10 t -Bu 94:6 (48 h) 92:8 o -Tol Cy t -Bu

STRUCTURAL EFFECT OF PN LIGAND ON REGIOSELECTIVITY O [Ru] 1 1 1 OH KO t -Bu O + O OH 4 acetone 4 4 30 °C, 1 h O diol:[Ru]:KO t -Bu = 100:1:1 A B >99% yield [diol] = 0.5 M H Ph 2 P NHR Ph 2 P N Ph 2 P NH 2 Ph 2 P NH 2 R = H 77:23 R Me 82:18 R = Ph 81:19 80:20 81:19 Bn 83:17 Bn 76:24 Ru R 2 P Cl R 2 P NH 2 Ph 2 P NH 2 Ph 2 P NH 2 NHR R = o -Tol 88:12 [Ru] Cy 96:4 90:10 t -Bu 94:6 (48 h) 92:8 o -Tol Cy t -Bu

STRUCTURAL EFFECT OF PN LIGAND ON REGIOSELECTIVITY O [Ru] 1 1 1 OH KO t -Bu O + O OH 4 acetone 4 4 30 °C, 1 h O diol:[Ru]:KO t -Bu = 100:1:1 A B >99% yield [diol] = 0.5 M H Ph 2 P NHR Ph 2 P N Ph 2 P NH 2 Ph 2 P NH 2 R = H 77:23 R Me 82:18 R = Ph 81:19 80:20 81:19 Bn 83:17 Bn 76:24 Ru R 2 P Cl R 2 P NH 2 Ph 2 P NH 2 Ph 2 P NH 2 NHR R = o -Tol 88:12 [Ru] Cy 96:4 90:10 t -Bu 94:6 (48 h) 92:8 o -Tol Cy t -Bu

STRUCTURAL EFFECT OF PN LIGAND ON REGIOSELECTIVITY O [Ru] 1 1 1 OH KO t -Bu O + O OH 4 acetone 4 4 30 °C, 1 h O diol:[Ru]:KO t -Bu = 100:1:1 A B >99% yield [diol] = 0.5 M H Ph 2 P NHR Ph 2 P N Ph 2 P NH 2 Ph 2 P NH 2 R = H 77:23 R Me 82:18 R = Ph 81:19 80:20 81:19 Bn 83:17 Bn 76:24 Ru R 2 P Cl R 2 P NH 2 Ph 2 P NH 2 Ph 2 P NH 2 NHR R = o -Tol 88:12 [Ru] Cy 96:4 90:10 t -Bu 94:6 (48 h) 92:8 o -Tol Cy t -Bu

STERIC HINDERANCE BETWEEN SUBSTITUENT ON PHOSPHINE AND SUBSTRATE ■ effect of the substituent on phosphine Ph 2 P NH 2 ( o -Tol) 2 P NH 2 ( t -Bu) 2 P NH 2 Cy 2 P NH 2 77:23 88:12 94:6 96:4 ■ Possible transition state Dehydrogenation of alcohol at 1 position H Ph H Hindered! C2 H Ru 4 1 H P C1 H N O O H H Regioselectivity: High R Kuhn, L. P.; Schleyer, P. R.; Baitinger, Jr., W. F.; Eberson, L. J. Am. Chem. Soc . 1964 , 86 , 650.

THE REACTIONS OF Cp*Ru(PN) AND 2,6-XyNC OTf X 2,6-XyNC Ru or Ru Ru R 2 P R 2 P Cl CH 2 Cl 2 R 2 P NCMe CNXy NH 2 rt NH 2 NH 2 X = Cl or OTf A B PN Ligand yield, % PN Ligand yield, % precursor precursor Ph 2 P NH 2 Ph 2 P NH 2 B 46 A 66 (77:23) (81:19) ( o -Tol) 2 P NH 2 Ph 2 P NH 2 A 72 B 92 (88:12) ( t- Bu) 2 P NH 2 (92:8) A 65 (94:6) 2,6-XyNC CN

CRYSTAL STRUCTURE OF Cp*Ru(XyNC)(PN): ETHYLENE CHAIN Ph 2 P NH 2 ( o -tol) 2 P NH 2 ( t- Bu) 2 P NH 2 Ru Ru Ru C １ C １ N1 P P N1 N1 C １ P C2 C2 C2 C 2/ c (#15) P 2 1 / n (#14) P 2 1 / c (#14) R 1 = 0.059 R 1 = 0.056 R 1 = 0.059 wR2 = 0.197 w R 2 = 0.166 w R 2 = 0.153 o-Tol t -Bu Ph Regioselectivity 77:23 88:12 94:6 ∠ C1-P-C2 = 101.6(2) ° ∠ C1-P-C2 = 105.51 (18) ° ∠ C1-P-C2 = 109.0(2) ° ∠ Ct-Ru-P-C2 = 97.28 ° ∠ Ct-Ru-P-C2 = 105.87 ° ∠ Ct-Ru-P-C2 = 107.37 ° ∠ Ct-Ru-P-C1 = –28.70 ° ∠ Ct-Ru-P-C1 = –25.47 ° ∠ Ct-Ru-P-C1 = –27.33 ° XyNC dihedral angle : (C 2 )Ar θ Cp* Ru C1-P-C2 P NH 2 XyNC Ru (C 1 )Ar The regioselectivity is better NH 2 P as ∠ C1-P-C2 is larger. C2 The regioselectivity is better C1 as ∠ Ct-Ru-P-C2 is larger.

EFFECT OF THE ANGLES ■ Effect of the angle formed by C1-P-C2 Large steric hinderance between alkyl group on phosphine H and substrate Ph H C2 H Ru 4 H 1 P C1 H High regioselectivity N O O H H R ■ Effect of the dihedral angle Large dihedral angle H H H Large steric hinderance between ligand and substrate H C2 O P Ru O H C1 N H High regioselectivity R Top view

CRYSTAL STRUCTURE OF Cp*Ru(XyNC)(PN): PROPYLENE CHANE Ph 2 P NH 2 Ph 2 P NH 2 Ph 2 P NH 2 Ru C １ Ru C3 C2 C3 Ru C １ C2 P N1 C １ N1 N2 P N1 P C2 _ C 2/ c (#15) P 1 (#2) P 2 1 / c (#14) R 1 = 0.056 R 1 = 0.049 R 1 = 0.065 w R 2 = 0.166 w R 2 = 0.132 w R 2 = 0.229 77:23 82:18 92:8 Regioselectivity ∠ C1-P-C2 = 101.6(2) ° ∠ C1-P-C2 = 103.2(2) ° ∠ C1-P-C2 = 104.1(3) ° ∠ Ct-Ru-P-C2 = 97.28 ° ∠ Ct-Ru-P-C2 = 83.85 ° ∠ Ct-Ru-P-C2 = 98.38 ° ∠ Ct-Ru-P-C1 = –28.70 ° ∠ Ct-Ru-P-C1 = –38.67 ° ∠ Ct-Ru-P-C1 = –24.34 °

SUMMARY ■ Regioselective lactonization of unsymmetrical diols O Cp*RuCl(PN) KO t -Bu OH O + O OH acetone 30 °C O diol:Ru:KO t -Bu = 100:1:1 A >99% B [diol] = 0.5 M R 2 P NH 2 Ph 2 P NH 2 Ph 2 P NH 2 Ru R 2 P Cl NHR R 88:12 90:10 92:8 R = o -tol R R R Cy 96:4 CpRu(PN) ■ The structural bulkiness around phosphine is important for the regioselectivity.