Reagent-controlled stereoselection in radical addition to α-methylenebutyrolactones
作者:Hirokazu Urabe、Katsushige Kobayashi、Fumie Sato
DOI:10.1039/c39950001043
日期:——
Some β- or γ-substituted α-methylenebutyrolactones are butylated with Bul and (Me3Si)3SiH to give cis-α,β- or -α,γ-disubstituted lactones in high selectivites, while the same reaction with Bu3SnH in the presence of bulky Lewis acid reverses the stereoselectivity to give a trans-disubstituted lactone as the major product.
Die α‐Methylen‐γ‐butyrolactone 1‐28 wurden auf molluskizide Wirkung gegen Biomphalaria glabrata untersucht. Die racem. Verbindung 25 ist am wirksamsten. Die Synthese erfolgte durch modifizierte Reformatzky‐Reaktion aus den entspr. Carbonylverbindungen und Brommethylacrylsäureethylester. 7‐10, 17 und 22‐27 wurden erstmalig synthetisiert.
The 1-trimethylsilylmethylvinyl group, as a 1-hydroxymethylvinyl equivalent, was readily introduced to epoxides with the corresponding Grignard reagent derived from 2-bromoallyltrimethylsilane. Obtained 2-(2-hydroxy-ethyl)-allylsilanes were converted to α-methylene-γ-lactones via diols.
Tailored α-methylene-γ-butyrolactones and their effects on growth suppression in pancreatic carcinoma cells
作者:P. Veeraraghavan Ramachandran、Debarshi Pratihar、Hari Narayanan G. Nair、Matthew Walters、Sadie Smith、Michele T. Yip-Schneider、Huangbing Wu、C. Max Schmidt
DOI:10.1016/j.bmcl.2010.09.022
日期:2010.11
A selected series of racemic alpha-methylene-gamma-butyrolactones (AMGBL) were synthesized via allylboration and screened against three human pancreatic cancer cell lines (Panc-1, MIA PaCa-2, and BxPC-3). This systematic study established a discernible relationship between the substitution pattern of AMGBL and their anti-proliferative activity. beta,gamma-diaryl-AMGBLs, particularly those with a trans-relationship exhibited higher potency than parthenolide and LC-1 against all three cell lines. (C) 2010 Elsevier Ltd. All rights reserved.
A One-Pot C–H Insertion/Olefination Sequence for the Formation of α-Alkylidene-γ-butyrolactones
作者:Matthew G. Lloyd、Richard J. K. Taylor、William P. Unsworth
DOI:10.1021/ol501092m
日期:2014.5.16
A one-pot C-H insertion/olefination sequence for the conversion of alpha-diazo-alpha-(dialkoxyphosphoryl)acetates into alpha-alkylidene-gamma-butyrolactones is reported. The key C-H insertion process is achieved using a catalytic amount of a dirhodium carboxylate catalyst, using operationally simple conditions. The size and electronic properties of the attached substituents were found to influence the regio- and diastereoselectivity of the process. The utility of the process is demonstrated by the synthesis of a known Staphylococcus aureus (MRSA) virulence inhibitor.