Synthetic studies on optically active .BETA.-lactams. II. Asymmetric synthesis of .BETA.-lactams by (2+2)cyclocondensation using heterocyclic compounds derived from L-(+)-tartaric acid, (S)- or (R)-glutamic acid, and (S)-serine as chiral auxiliaries.
作者:Nobuo IKOTA
DOI:10.1248/cpb.38.1601
日期:——
Asymmetric synthesis of β-lactams by the [2+2]cyclocondensation of an imine (7) to chiral ketene species (2b, 4b, and 6c) bearing heterocycles derived from L-(+)-tartaric acid, (S)-glutamic acid, and (S)-serine was carried out. The reaction of 2b with 7 gave the trans-β-lactams with 74% diastereomeric excess, and cis-β-lactams were predominantly formed with high diastereomeric purity (up to 96%) when 4b and 6c were employed. Asymmetric synthesis of (3S, 4S)- and (3R, 4R)-1-benzyl-3[(benzyloxycarbonyl)amino]-4-hydroxymethyl-2-azetidinones (26 and 30g) using (R)-4b as a ketene species and the chiral imine (21) prepared from L-(+)-tartaric acid was also achieved.
通过由L-(+)-酒石酸、(S)-谷氨酸和(S)-丝氨酸衍生的杂环基团修饰的手性烯酮物种(2b、4b和6c)与亚胺(7)的[2+2]环加成反应,进行了β-内酰胺的不对称合成。2b与7的反应生成了具有74%非对映异构体过剩的反式β-内酰胺,而使用4b和6c时主要生成了高度非对映纯(高达96%)的顺式β-内酰胺。还实现了使用(R)-4b作为烯酮物种和从L-(+)-酒石酸制备的手性亚胺(21)合成(3S, 4S)-和(3R, 4R)-1-苄基-3[(苄氧羰基)氨基]-4-羟甲基-2-氮杂环丁酮(26和30g)的不对称合成。