Group-Selective Hydroalumination:  A Novel Route to Stereogenic <i>tert</i>-Alcohol Centers

Ohmori, Ken; Suzuki, Takao; Taya, Kimiko; Tanabe, Daisuke; Ohta, Toshihiro; Suzuki, Keisuke

doi:10.1021/ol0156704

Cited by 20 publications

(11 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All solvents were distilled and stored in solvent reservoirs which contained 4 A ˚molecular sieves and were purged with nitrogen. 1 H and 13 C NMR spectra were recorded on a Bruker Avance 300 spectrometer. Chemical shifts for 1 H and 13 C spectra were recorded in ppm relative to the residual protons and 13 C of CDCl 3 (d 7.24, 77.0) and C 6 D 6 (d 7.15, 128.0).…”

Section: Experimental Physical Measurements and Materialsmentioning

confidence: 99%

“…1 H and 13 C NMR spectra were recorded on a Bruker Avance 300 spectrometer. Chemical shifts for 1 H and 13 C spectra were recorded in ppm relative to the residual protons and 13 C of CDCl 3 (d 7.24, 77.0) and C 6 D 6 (d 7.15, 128.0). Elemental analyses were performed on a Heraeus CHN-OS Rapid Elemental Analyzer at the Instrument Center, NCHU.…”

Section: Experimental Physical Measurements and Materialsmentioning

confidence: 99%

“…10 (d,2H,. 13 4 The molecular structure of 3, the ellipsoids were drawn at 50% probability level and all hydrogen atoms were omitted for clarity.…”

Section: Preparation Of the Complexesmentioning

confidence: 99%

“…1 H NMR (CDCl 3 ): 1.15 (d, 3 J = 13.5 Hz, 12H, CHMe 2 ), 2.29 (s, 3H, p-PhMe), 2.36 (s, 6H, o-PhMe), 2.38 (s, 12H, NMe 2 ), 3.41 (m, 2H, CHMe 2 ), 3.57, 3.64 (dd, 2 J = 21.0 Hz, 3 J = 13.5 Hz, 4H, CH 2 N), 4.08 (s, 1H, OC=CH 2 ), 4.38 (s, 1H, OC=CH 2 ), 5.98 (s, 2H, pyrrole CH), 6.80-7.07 (m, 5H, phenyl CH). 13 C NMR (CDCl 3 ): 20.5 (q, J CH = 126 Hz, o-PhMe), 21.0 (q, J CH = 120 Hz, p-PhMe), 24.2 (q, J CH = 125 Hz, CHMe 2 ), 25,7 (d, J CH = 126 Hz, CHMe 2 ), 47.3 (q, J CH = 137 Hz, NMe 2 ), 60.6 (t, J CH = 138 Hz, CH 2 N), 91.6(dd, J CH = 159, 158 Hz, OC=CH 2 ), 104.5 (d, Al: C,72.63;H,8.87;N,7.70. Found: C,72.87;H,8.62; N, 7.45%.…”

Section: Figmentioning

confidence: 99%

“…Several hydroalumination reactions have been investigated before either involving trialkylaluminiums or dialkylaluminium hydrides with dialkylaluminium acetylides 12 or using bis-alkynyl alcohols having an adjacent stereogenic center which provides access to stereo-defined tert-alcohols. 13 The reactivity of two sterically bulky amidines, ArNC(R)N(H)Ar [Ar = 2,6-diisopropylphenyl; R = H (HFiso); tBu, (HPiso)] towards aluminium have examined before 14 and the structural motif generated by the prepared complexes are rationalized in terms of the steric bulk of the amidinate ligands and electronic properties of metal. , having stability for use in chemical vapor deposition and related applications.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Deprotonation and reductive addition reactions of hypervalent aluminium dihydride compounds containing substituted pyrrolyl ligands with phenols, ketones, and aldehydes

Chen

et al. 2009

Dalton Trans.

View full text Add to dashboard Cite

The reactivities of [C4H2N(CH2NMe2)2]AlH2 (1) with primary and secondary amines, phenols, ketones, and phenyl isothiocyanate were examined. Reactions of 1 with one or two equivalents of 2,6-dichloroaniline in methylene chloride generated [C4H2N(CH2NMe2)2]AlH(NHC6H3-2,6-Cl2) (2) and [C4H2N(CH2NMe2)2]Al(NHC6H3-2,6-Cl2)2 (3), respectively, following hydrogen elimination. Similarly, the reactions of 1 with one or two equivalents of carbazole afforded [C4H2N(CH2NMe2)2]AlH(NC12H8) (4) or [C4H2N(CH2NMe2)2]Al(NC12H8)2 (5) by deprotonating the acidic N-H of carbazole. Reacting 1 with one equivalent of 2,6-diisopropylphenol in diethyl ether formed an aluminium phenoxo compound [C4H2N(CH2NMe2)2]AlH(OC6H3-2,6-iPr2) (6), by deprotonation of phenol as well with the elimination of one equivalent hydrogen. Further reaction of 6 with one equivalent of 2,4,6-trimethylacetophenone in methylene chloride generated [C4H2N(CH2NMe2)2]Al(OC6H3-2,6-iPr2)[OC(=CH2)(C6H2-2,4,6-Me3)] (7) by deprotonating the methyl proton of the acetophenone. Similar deprotonation occurred when 1 reacted with two equivalents of 2,4,6-trimethylacetophenone in methylene chloride to generate [C4H2N(CH2NMe2)2]Al[OC(=CH2)(C6H2-2,4,6-Me3)]2 (8). Compounds [C4H2N(CH2NMe2)2]Al(OCHPh2)2 (9), and [C4H2N(CH2NMe2)2]Al(SCHNPh)2 (10) could also be obtained by reacting 1 with two equivalents of benzophenone and phenyl isothiocyanate, respectively through hydroalumination. The 1H NMR spectra of 10 showed broad signals for the CH2N and NMe2 groups, which represent dynamical fluctuations of the molecules in solution state. The estimated energy barrier (DeltaG(c)(double dagger)) from the coalescence temperature for the fluctuation was estimated at 17.1 Kcal mol(-1). The solid-state structures of compounds 2, 3, 5, 7, 9, and 10 have been determined.

show abstract

Section: Experimental Physical Measurements and Materialsmentioning

confidence: 99%