Enantioselective alkynylations of aromatic and aliphatic aldehydes catalyzed by terpene derived chiral amino alcohols
作者:Cian Christopher Watts、Praveen Thoniyot、Lacie C. Hirayama、Talia Romano、Bakthan Singaram
DOI:10.1016/j.tetasy.2005.03.036
日期:2005.5
Enantioselective alkynyl zinc additions to aromatic and aliphatic aldehydes have been studied using terpene derived chiral amino alcohol ligands. The limonene derived amino alcohol (1R,2R,5S)-2-methyl-5-(1-methylethenyl)-2-(1-pyrrolidinyl)cyclohexanol gave the most promising results. Chiral propargylic alcohols were obtained in good yields and moderate enantioselectivities (up to 60%).
Chiral Macrocycle-Catalyzed Highly Enantioselective Phenylacetylene Addition to Aliphatic and Vinyl Aldehydes
作者:Zi-Bo Li、Tian-Dong Liu、Lin Pu
DOI:10.1021/jo070091j
日期:2007.6.1
The 1,1‘-binaphthyl macrocycle (S)-2 is found to be an excellent catalyst for the alkyne addition to aldehydes. In the presence of (S)-2 (20 mol %) and Me2Zn (2 equiv) in THF at room temperature, the addition of phenylacetylene to linear or branched aliphatic aldehydes and vinylaldehydes gave various propargylic alcohols with 89−96% ee.
new chiral β-hydroxy amide ligands were synthesized via the reaction of benzyl chloride and aminoalcohols derived from l-tyrosine. The titanium(IV) complex of chiral ligand 8b was found to be an effective catalyst for the asymmetric alkynylation of aliphatic, vinyl and aromatic aldehydes. The propargyl alcohols were obtained in highly enantiomeric excesses (up to 96% ee) under optimized conditions.
Camphor-based Schiff base ligand SBAIB: an enantioselective catalyst for addition of phenylacetylene to aldehydes
作者:Ramalingam Boobalan、Chinpiao Chen、Gene-Hsian Lee
DOI:10.1039/c1ob06683h
日期:——
series of Schiffbase ligands were synthesized from (1R)-camphor. Under the optimal conditions, (+)-SBAIB-a, 10 was found to be an excellent catalyst for the enantioselective addition of phenylacetylene to various aldehydes without utilizing either achiral additives or Ti(OiPr)4. This approach yielded (R)-propargylic alcohols in extremely high yields (up to 99%) and excellent enantioselectivities (up to
从中合成了一系列席夫碱配体 (1 R)-樟脑。在最佳条件下(+)-SBAIB-a,10被发现是用于对映选择性加成的极好的催化剂苯乙炔 无需使用非手性添加剂或 钛(O i Pr)4。该方法以极高的产率(高达99%)和优异的对映选择性(高达92%)产生了(R)-丙炔醇。相应的(S)-丙炔醇的合成具有良好的对映选择性(高达91%)和极好的收率(高达99%),使用(-)-SBAIB-a,41岁。
Catalytic Asymmetric Addition of Terminal Alkynes to Aldehydes Mediated by (1R,2R)-2-(Dimethylamino)- 1,2-diphenylethanol
Catalyticasymmetric alkynylation of aldehydes with terminalalkynes was catalyzed by zinc triflate and (1R,2R)-2-(dimethylamino)-1,2-diphenylethanol in toluene to give the corresponding alcohols with high enantiomeric excess up to 98% in good yields.