Cu(i)-catalyzed tandem benzyldiazoester coupling with terminal alkyne–allene formation–Michael reaction: Application to the syntheses of oxa and azacycles
A simple and practical procedure for the synthesis of aza- and oxacycles, which possess an array of stereogenic functionalities, is described. This protocol relies on tandem Cu-catalyzed coupling of suitably functionalized terminal alkyne with diazoester followed by isomerization and subsequent aza or oxa-Michael reaction, thus generating the required scaffold with high diastereoselectivity.
Alkaloids of the Mexican Bean Beetle, Epilachna varivestis (Coccinellidae)
作者:Athula B. Attygalle、Shang-Cheng Xu、Kevin D. McCormick、Jerrold Meinwald、Curtis L. Blankespoor、Thomas Eisner
DOI:10.1016/0040-4020(93)80019-p
日期:——
Two novel alkaloids, 2-(12-aminotridecyl)-pyrrolidine and its 1-(2-hydroxyethyl) derivative, are characterized from extracts of adult Mexican bean beetles. These pyrrolidines, together with a previously identified homotropane alkaloid, euphococcinine, account for 90% of the alkaloids present in this beetle. A number of piperidine derivatives are also identified as minor components. The total mixture represents the most complex bouquet of alkaloids reported hitherto from any coccinellid beetle.
A Novel Asymmetric Route to Chiral, Nonracemic cis-2,6-Disubstituted Piperidines. Synthesis of (+)-Pinidinone and (+)-Monomorine