Synthesis, including asymmetric synthesis, of 1-substituted cyclopentenes from cyclobutanones with one-carbon ring-expansion by 1,2-carbon-carbon insertion of magnesium carbenoids
作者:Tsuyoshi Satoh、Yu Awata、Yuichi Kato、Shingo Ogata、Masashi Ishigaki、Shimpei Sugiyama、Hideki Saitoh
DOI:10.1016/j.tet.2010.12.023
日期:2011.2
Treatment of 1-chlorovinyl p-tolyl sulfoxides, which were derived from cyclobutanones and chloromethyl p-tolyl sulfoxide, with lithium enolate of tert-butyl carboxylates, amides, lithium α-sulfonyl carbanions, and lithium α-carbanion of acetonitrile gave adducts in high to quantitative yields. The adducts were treated with Grignard regents, such as i-PrMgCl and EtMgCl in toluene to afford 1-substituted
1-氯乙烯基治疗p -甲苯基亚砜,这是从cyclobutanones和氯衍生p -甲苯基砜,与锂的烯醇叔丁基羧酸酯,酰胺,锂α磺酰基负碳离子,和锂α负离子乙腈中,得到高的加合物定量产量。用格氏试剂,例如i- PrMgCl和EtMgCl在甲苯中处理加合物,以高到高收率得到1-取代的环戊烯,并通过1,2-碳-碳(1,2-CC)进行一碳环扩环生成的镁类马鞭草中间体的插入反应。发现类胡萝卜素1,2-CC的插入具有高度立体特异性。当光学纯的氯甲基p在该步骤中使用-甲苯基亚砜,以高光学纯度获得了光学活性的1-取代的环戊烯。