Synthetic Approach to Hypoxyxylerone, Novel Inhibitor of Topoisomerase I
摘要:
[GRAPHICS]A potential route to the topoisomerase I inhibitor hypoxyxylerone is demonstrated by a highly convergent synthesis of the penta(O-methyl) derivative. The key step in the approach is an anionic homo-Fries rearrangement, little used to date in natural product synthesis and employed here for the first time with a dinaphthalenic substrate, to access the pentacyclic system of hypoxyxylerone.
A highly regio- and stereoselective Pd-catalyzed electrocarboxylation of Baylis-Hillman acetates: An interesting switchable regioselectivity based on electrode material
regio- and stereoselective palladium catalyzed electrocarboxylation of Baylis-Hillman acetates. We found an interesting unprecedented electrode material-controlled switchable regioselectivity. When Platinum was taken as cathode, benzylic carboxylation products were found to be the predominant regioisomers (condition A). Under similar reaction conditions when Nickel was taken as cathode, a complete reversal
我们开发了一种新型的区域选择性和立体选择性钯催化 Baylis-Hillman 醋酸盐的电羧化反应。我们发现了一种有趣的、前所未有的电极材料控制的可切换区域选择性。当铂作为阴极时,发现苄基羧化产物是主要的区域异构体(条件 A)。在以镍为阴极的类似反应条件下,观察到区域选择性完全逆转,提供肉桂基羧化产物作为主要的区域异构体,仅具有 (E)-立体化学(条件 B)。我们提出了合理的机制来解释区域选择性的转换,这得到了 TEMPO 实验的进一步支持。
RIZZACASA, MARK A.;SARGENT, MELVYN V., AUSTRAL. J. CHEM., 40,(1987) N 10, 1737-1743