查询词典 lactonization

A one-pot chemoselective reduction and lactonization of(4S,5R)-hemiesters was carried out to afford high-yielding(3aS,6aR)-lactone,a key chiral building block for the biotin synthesis. One-step introduction of carboxybutyl chain onto(3aS,6aR)-thiolactone was reached upon treatment of zinc reagent 25 in the presence of nanopalladium via an improved Fukuyama coupling under mild reaction conditions.

在侧链引入过程中，采用纳米钯LDH-Pd~0为催化剂以改进的Fukuyama偶联反应一步高效地引入-生物素五碳羧酸侧链，紧接着创造性地以离子氢化的方式建立了-生物素的第三个手性中心。

Chiral centers of C5 and C8 are directly constructed in the key step of the diastereoselective propargylation from D--tartrate. The methylation and subsequent methoxycarbonylation result in desymmetrization of the terminal dialkynes. The α,β-unsaturated δ-lactone is synthesized after partial hydrogenation and lactonization.

由非天然酒石酸出发，利用双向非对映选择性的炔丙基化反应，在一步反应中同时构建C5和C8手性中心；然后通过末端炔基的甲基化、甲酯基化，延长碳链并对分子去对称化；内酯化得到关键中间体α，β-不饱和六元内酯，再经多步反应转化得到8-epi--Boronolide。

Through diazotization-lactonization,esterification, reduction, ether formation and double bond formation,the optically active--γ-benzyloxy methy-γ-butanolideXXIII and--γ-benzyloxy mothy-γ- butenolideXXV were preparedstarting from L-glutamic acid.

本论文采用易得的L-谷氨酸为原料，经重氮化-内酯化、酯化、还原、醚化和形成双键五步反应，合成了光学活性的化合物XXIII和XXV(Scheme 6，P.63)。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。