RESUMO
A concise, modular and efficient synthesis of the title natural products is reported. Prominent steps include (i) one-pot assembly of a key ß-aryl-α-benzoylbutenolide building block by regiocontrolled "click-unclick" oxazole-ynone Diels-Alder cycloaddition/cycloreversion and ensuing 2-alkoxyfuran hydrolysis and (ii) a protecting group-free vinylogous Knoevenagel condensation enabling rapid access to cadiolides A, B, and D from a common precursor.
Assuntos
4-Butirolactona/análogos & derivados , Antibacterianos/síntese química , Urocordados/química , 4-Butirolactona/síntese química , 4-Butirolactona/química , Animais , Antibacterianos/química , Organismos Aquáticos/química , Ciclização , Estrutura MolecularRESUMO
Production of cloned embryos by nuclear transfer from adult somatic cells is a novel and promising technique in animal biotechnology. In spite of numerous reported viable offspring in various species, the efficiency of the technique remains very low. Embryonic and fetal mortality occurs all along pregnancy and during the peri-natal life, even months after birth. Both embryonic and placental dysfunctions might be involved. However the precise causes of such developmental failures are still unknown. In the present review, we report data from different studies which described the main defaults which have been observed after embryonic cloning in various species. The putative molecular and cellular causes of these developmental failures are discussed.