Direct furan formation by treatment of alkynyl ketones with strong potassium bases
作者:David I. MaGee、James D. Leach、Santosa Setiadji
DOI:10.1016/s0040-4020(99)00063-0
日期:1999.3
The reaction of keto-alkynes with strong potassium bases such as KOtBu, KHMDS or KH yields substituted furans in moderate to good yields without any special activation of the alkyne required. The method offers both a flexibility and rapid method for the synthesis of di- tri- or tetra-substituted furans, although some yields are only modest at best.
Synthetic studies and mechanistic observations in nickel-catalyzed polycyclizations
作者:John Montgomery、Jeongbeob Seo
DOI:10.1016/s0040-4020(97)10213-7
日期:1998.2
A series of polyunsaturated enones were investigated in Ni(COD)2 / organozinc - mediated cyclizations. One substrate class underwent an efficient [2+2+2] cycloaddition reaction to generate a tricyclic ring system from a linear precursor. A discussion of probable mechanisms is provided.
Gold(I)-Catalyzed Desymmetrization of 1,4-Dienes by an Enantioselective Tandem Alkoxylation/Claisen Rearrangement
作者:Hongmiao Wu、Weiwei Zi、Guigen Li、Hongjian Lu、F. Dean Toste
DOI:10.1002/anie.201503357
日期:2015.7.13
An enantioselective alkoxylation/Claisen rearrangement reaction was achieved by a strategic desymmetrization of 1,4‐dienes under the catalysis of (S)‐DTBM‐Segphos(AuCl)2/AgBF4. This reaction system was highly selective for the formation of 3,3‐rearrangement products, providing cycloheptenes with various substitutions in good yield and good to excellent enantioselectivity. This transformation was further
Low-valenttitanium(II) complexes turned out to be suitable reagents in the promotion of alkyne/alkoxyallene coupling reactions in an intramolecular fashion. The conditions developed herein led to a broad range of highly functionalized cyclic adducts with excellent regioselectivities toward the central carbon of the alkoxyallene moiety. Good yields (up to 76%) were obtained over 19 examples. One-pot
低价钛( II )配合物被证明是促进分子内方式的炔烃/烷氧基丙二烯偶联反应的合适试剂。本文开发的条件产生了多种高度官能化的环状加合物,对烷氧基丙二烯部分的中心碳具有优异的区域选择性。 19 个实施例均获得了良好的产率(高达 76%)。通过亲电试剂捕获进行的一锅后期官能化也是可能的,并产生优异的非对映选择性(高达 95/5 dr)。