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Highly enantioselective arylation of aldehydes and ketones using AlArEt(2)(THF) as aryl sources.
J Org Chem. 2009 May 01; 74(9):3500-5.JO

Abstract

A series of AlArEt(2)(THF) (Ar = Ph (1a), 4-MeC(6)H(4) (1b), 4-MeOC(6)H(4) (1c), 4-Me(3)SiC(6)H(4) (1d), 2-naphthyl (1e)) were synthesized from reactions of AlEt(2)Br(THF) with ArMgBr. In CDCl(3) solution, the (1)H NMR spectra showed that AlArEt(2)(THF) compounds exist as a mixture of four species of formulas of AlAr(x)Et(3-x) (THF) (x = 0, 1, 2, or 3). AlArEt(2)(THF) compounds were found to be superior and atom-economic reagents for asymmetric aryl additions to organic carbonyls. Aryl additions of AlArEt(2)(THF) to aldehydes catalyzed by the titanium(IV) complex of (R)-H(8)-BINOL were efficient with a short reaction time of 1 h, affording aryl addition products as exclusive or main products in high yields and excellent enantioselectivities of up to 98% ee. Although ethyl additions to aldehydes occurred in minor extent, this study demonstrates that increasing the amount of AlArEt(2)(THF) from 1.2 to 1.4 or to 1.6 equiv significantly improved the aryl addition products of up to >99%. On the other hand, asymmetric arylations of AlArEt(2)(THF) to ketones employing a titanium(IV) catalyst of (S)-BINOL produced optically active tertiary alcohols exclusively in excellent enantioselectivities of up to 94% ee.

Authors+Show Affiliations

Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19338270

Citation

Zhou, Shuangliu, et al. "Highly Enantioselective Arylation of Aldehydes and Ketones Using AlArEt(2)(THF) as Aryl Sources." The Journal of Organic Chemistry, vol. 74, no. 9, 2009, pp. 3500-5.
Zhou S, Wu KH, Chen CA, et al. Highly enantioselective arylation of aldehydes and ketones using AlArEt(2)(THF) as aryl sources. J Org Chem. 2009;74(9):3500-5.
Zhou, S., Wu, K. H., Chen, C. A., & Gau, H. M. (2009). Highly enantioselective arylation of aldehydes and ketones using AlArEt(2)(THF) as aryl sources. The Journal of Organic Chemistry, 74(9), 3500-5. https://doi.org/10.1021/jo900348p
Zhou S, et al. Highly Enantioselective Arylation of Aldehydes and Ketones Using AlArEt(2)(THF) as Aryl Sources. J Org Chem. 2009 May 1;74(9):3500-5. PubMed PMID: 19338270.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Highly enantioselective arylation of aldehydes and ketones using AlArEt(2)(THF) as aryl sources. AU - Zhou,Shuangliu, AU - Wu,Kuo-Hui, AU - Chen,Chien-An, AU - Gau,Han-Mou, PY - 2009/4/3/entrez PY - 2009/4/3/pubmed PY - 2009/8/6/medline SP - 3500 EP - 5 JF - The Journal of organic chemistry JO - J. Org. Chem. VL - 74 IS - 9 N2 - A series of AlArEt(2)(THF) (Ar = Ph (1a), 4-MeC(6)H(4) (1b), 4-MeOC(6)H(4) (1c), 4-Me(3)SiC(6)H(4) (1d), 2-naphthyl (1e)) were synthesized from reactions of AlEt(2)Br(THF) with ArMgBr. In CDCl(3) solution, the (1)H NMR spectra showed that AlArEt(2)(THF) compounds exist as a mixture of four species of formulas of AlAr(x)Et(3-x) (THF) (x = 0, 1, 2, or 3). AlArEt(2)(THF) compounds were found to be superior and atom-economic reagents for asymmetric aryl additions to organic carbonyls. Aryl additions of AlArEt(2)(THF) to aldehydes catalyzed by the titanium(IV) complex of (R)-H(8)-BINOL were efficient with a short reaction time of 1 h, affording aryl addition products as exclusive or main products in high yields and excellent enantioselectivities of up to 98% ee. Although ethyl additions to aldehydes occurred in minor extent, this study demonstrates that increasing the amount of AlArEt(2)(THF) from 1.2 to 1.4 or to 1.6 equiv significantly improved the aryl addition products of up to >99%. On the other hand, asymmetric arylations of AlArEt(2)(THF) to ketones employing a titanium(IV) catalyst of (S)-BINOL produced optically active tertiary alcohols exclusively in excellent enantioselectivities of up to 94% ee. SN - 1520-6904 UR - https://www.unboundmedicine.com/medline/citation/19338270/Highly_enantioselective_arylation_of_aldehydes_and_ketones_using_AlArEt_2__THF__as_aryl_sources_ L2 - https://dx.doi.org/10.1021/jo900348p DB - PRIME DP - Unbound Medicine ER -