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Room temperature and highly enantioselective additions of alkyltitanium reagents to aldehydes catalyzed by a titanium catalyst of (R)-H8-binol.
Chirality. 2011 Nov; 23(10):929-39.C

Abstract

Three alkyltitanium reagents of RTi(O-i-Pr)3 (R = Cy (1a), i-Bu (1b), and n-Bu (1c)) were prepared in good yields. The high-resolution mass spectroscopy showed that and 1c in the gas phase are monomeric species. However, the solid state of 1a revealed a dimeric structure. Asymmetric additions of 1a-1c to aldehydes catalyzed by a titanium catalyst of (R)-H8 -BINOL were studied at room temperature. The reactions produced desired secondary alcohols in good yields with good to excellent enantioselectivities of up to 94% ee. Reactivity and enantioselectivity differences, in terms of steric bulkiness of the R nucleophiles, are herein described. The addition reactions of secondary c-hexyl to aldehydes were slower than the reactions of primary i-butyl or n-butyl nucleophiles. For the primary alkyls, lower enantioselectivities were obtained for products from addition reactions of the linear n-butyl as compared with the enantioselectivities of products from the addition reactions of the branched i-butyl group. The same stereochemistry of RTi(O-i-Pr)3 addition reactions as the addition reactions of organozinc, organoaluminum, Grignard, or organolithium reagents directly supports the argument of that titanium-catalyzed addition reactions of aldehydes involve an addition of an organotitanium nucleophile.

Authors+Show Affiliations

Department of Chemistry, National Chung Hsing University, Taichung, Taiwan, Republic of China; College of Chemistry and Environmental Protection Engineering, Southwest University for Nationalities, Chengdu, People's Republic of China.No affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

21953806

Citation

Li, Qinghan, and Han-Mou Gau. "Room Temperature and Highly Enantioselective Additions of Alkyltitanium Reagents to Aldehydes Catalyzed By a Titanium Catalyst of (R)-H8-binol." Chirality, vol. 23, no. 10, 2011, pp. 929-39.
Li Q, Gau HM. Room temperature and highly enantioselective additions of alkyltitanium reagents to aldehydes catalyzed by a titanium catalyst of (R)-H8-binol. Chirality. 2011;23(10):929-39.
Li, Q., & Gau, H. M. (2011). Room temperature and highly enantioselective additions of alkyltitanium reagents to aldehydes catalyzed by a titanium catalyst of (R)-H8-binol. Chirality, 23(10), 929-39. https://doi.org/10.1002/chir.21018
Li Q, Gau HM. Room Temperature and Highly Enantioselective Additions of Alkyltitanium Reagents to Aldehydes Catalyzed By a Titanium Catalyst of (R)-H8-binol. Chirality. 2011;23(10):929-39. PubMed PMID: 21953806.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Room temperature and highly enantioselective additions of alkyltitanium reagents to aldehydes catalyzed by a titanium catalyst of (R)-H8-binol. AU - Li,Qinghan, AU - Gau,Han-Mou, Y1 - 2011/09/26/ PY - 2011/05/05/received PY - 2011/07/06/accepted PY - 2011/9/29/entrez PY - 2011/9/29/pubmed PY - 2015/6/25/medline KW - BINOL derivative KW - H8-(R)-BINOL KW - alkyl addition KW - alkyltitanium triisopropoxide KW - asymmetric catalysis KW - titanium catalyst SP - 929 EP - 39 JF - Chirality JO - Chirality VL - 23 IS - 10 N2 - Three alkyltitanium reagents of RTi(O-i-Pr)3 (R = Cy (1a), i-Bu (1b), and n-Bu (1c)) were prepared in good yields. The high-resolution mass spectroscopy showed that and 1c in the gas phase are monomeric species. However, the solid state of 1a revealed a dimeric structure. Asymmetric additions of 1a-1c to aldehydes catalyzed by a titanium catalyst of (R)-H8 -BINOL were studied at room temperature. The reactions produced desired secondary alcohols in good yields with good to excellent enantioselectivities of up to 94% ee. Reactivity and enantioselectivity differences, in terms of steric bulkiness of the R nucleophiles, are herein described. The addition reactions of secondary c-hexyl to aldehydes were slower than the reactions of primary i-butyl or n-butyl nucleophiles. For the primary alkyls, lower enantioselectivities were obtained for products from addition reactions of the linear n-butyl as compared with the enantioselectivities of products from the addition reactions of the branched i-butyl group. The same stereochemistry of RTi(O-i-Pr)3 addition reactions as the addition reactions of organozinc, organoaluminum, Grignard, or organolithium reagents directly supports the argument of that titanium-catalyzed addition reactions of aldehydes involve an addition of an organotitanium nucleophile. SN - 1520-636X UR - https://www.unboundmedicine.com/medline/citation/21953806/Room_temperature_and_highly_enantioselective_additions_of_alkyltitanium_reagents_to_aldehydes_catalyzed_by_a_titanium_catalyst_of__R__H8_binol_ L2 - https://doi.org/10.1002/chir.21018 DB - PRIME DP - Unbound Medicine ER -