α'-羟基烯酮作为路易斯酸催化对映选择性狄尔斯-阿尔德反应的非手性模板

Alpha'-hydroxy enones as achiral templates for Lewis acid-catalyzed enantioselective Diels-Alder reactions.

作者信息

Palomo Claudio, Oiarbide Mikel, García Jesús M, González Alberto, Arceo Elena

机构信息

Departamento de Química Orgánica I, Facultad de Química, Universidad del País Vasco, Apdo. 1072, 20080 San Sebastián, Spain.

出版信息

J Am Chem Soc. 2003 Nov 19;125(46):13942-3. doi: 10.1021/ja0368002.

DOI:10.1021/ja0368002

PMID:14611214

Abstract

alpha'-Hydroxy enones react with dienes in the presence of (S,S)-Cu(tBu-box)2 or (S,S)-Cu(tBu-box)2 (2 to 10 mol %) to afford the corresponding Diels-Alder adducts in high yield and selectivity. Isomeric ratios (regioselectivity, endo/exo or cis/trans) of up to >99:1 and ee values of up to >99% are obtained. Significantly, difficult dienes such as isoprene, 2,3-dimethyl butadiene and piperylene behave satisfactorily. Subsequent oxidative cleavage of the ketol in the resulting cycloadducts by treatment with cerium ammonium nitrate (CAN) yields the corresponding enantiopure carboxylic acids. Alternatively, carbonyl addition and subsequent diol cleavage with CAN produces the corresponding ketone adducts.

摘要

α'-羟基烯酮在（S,S）-Cu（tBu-box）₂ 或（S,S）-Cu（tBu-box）₂（2至10摩尔%）存在下与二烯反应，以高产率和选择性得到相应的狄尔斯-阿尔德加合物。获得了高达>99:1的异构体比例（区域选择性、内型/外型或顺式/反式）和高达>99%的对映体过量值。值得注意的是，诸如异戊二烯、2,3-二甲基丁二烯和间戊二烯等难反应的二烯表现令人满意。通过用硝酸铈铵（CAN）处理，对所得环加合物中的酮醇进行后续氧化裂解，得到相应的对映体纯羧酸。或者，羰基加成以及随后用CAN进行二醇裂解产生相应的酮加合物。