Addition en 1,8 d'organocuprates lithiens saturés sur la cétone CH3 (CHCH)3COCH3 et sur l'ester CH3(CHCH)3COOC2H5
作者:F. Barbot、A. Kadib-Elban、Ph. Miginiac
DOI:10.1016/0022-328x(88)80253-5
日期:1988.5
The reaction of saturated lithium organocuprates with the trienic ketone CH3(CHCH)3COCH3 and with the trienic ester CH3 (CHCH)3COOC2H5 proceeds by a 1,8 conjugate addition to give a β,δ-diethylenic carboynl compound.
An efficient Ir(III) dihydride complex catalyzed 1,3-rearrangement of allylicalcohols was realized, affording the corresponding less easily accessible allylicalcohols regio- and stereoselectively in high yields from readily available starting materials. The reaction pathway involves a π-allyl-Ir(V) intermediate and the dihydride in Ir(III) dihydride complex acts as the hydrogen switch to modulate
The iterativepolyketidesynthases from the biosynthetic pathways of three enediyne natural products were examined. The results established the all-trans conjugated pentadecaheptanene as the only major product shared by the PKSs. The experiments further revealed some intrinsic differences among the PKSs by demonstrating the formation of different by-products.
<i>In Vitro</i> Reconstitution of Cinnamoyl Moiety Reveals Two Distinct Cyclases for Benzene Ring Formation
作者:Jing Shi、Yang Shi、Jian Cheng Li、Wanqing Wei、Yu Chen、Ping Cheng、Cheng Li Liu、Hao Zhang、Rui Wu、Bo Zhang、Rui Hua Jiao、Shouyun Yu、Yong Liang、Ren Xiang Tan、Hui Ming Ge
DOI:10.1021/jacs.2c02855
日期:2022.5.4
with notable bioactivities. The biosynthesis of cinnamoyl moiety has been proposed to be assembled by an unusual highly reducing (HR) type II polyketide synthases (PKS). However, the biosynthetic route, especially the cyclization step for the benzene ring formation, remains unclear. In this work, we successfully reconstituted the pathway of cinnamoyl moiety in kitacinnamycin biosynthesis through a
含肉桂酰的天然产物 (CCNPs) 是一小类具有显着生物活性的细菌代谢物。已提出肉桂酰基部分的生物合成由不寻常的高度还原 (HR) II 型聚酮化合物合酶 (PKS) 组装。然而,生物合成路线,特别是苯环形成的环化步骤仍不清楚。在这项工作中,我们通过体外逐步方法成功地重建了肉桂酰部分在 kitacinnamycin 生物合成中的途径并证明了一种三蛋白复合物Kcn17-Kcn18-Kcn19可以催化6π-电环化,然后脱氢形成苯环。我们发现三蛋白同源物广泛分布在 207 个 HR II 型 PKS 生物合成基因簇中,包括五个已知的 CCNP。相比之下,在优素芬(一种含肉桂酰的多烯)的生物合成中,我们发现苯环的形成是由一种独特的孤儿蛋白完成的。因此,我们的工作解决了肉桂酰生物合成中长期存在的谜团,并揭示了两种不同的酶,它们可以通过多烯前体合成苯环。