A Practical Synthesis of Nelfinavir, an HIV-Protease Inhibitor, Using a Novel Chiral C4 Building Block: (5R,6S)-2,2-Dimethyl-5-hydroxy-1,3-dioxepan-6-ylammonium Acetate
Kinetic resolution of 2-mono- and 2,2-disubstituted epoxides was accomplished using epoxide hydrolases from bacterial and fungal origin by employing lyophilized whole microbial cells. In all cases investigated, the biocatalytic hydrolysis was shown to proceed with retention of configuration at the stereogenic center leading to 1,2-diols and remaining epoxides. The selectivity of the reaction was dependent
Abstract Starting from a chiralmethylenecyclopropane building block, readily obtained by enzymatic desymmetrization of a meso-diol, two types of methylenecyclopropane analogues of nucleosides were synthesized. The first type of nucleosides was obtained from the direct coupling of the chiral building block with 6-chloropurine under Mitsunobu reaction conditions followed by the functionalization of
Single-Event Spectroscopy and Unravelling Kinetics of Covalent Domains Based on Cyclobutane Mechanophores
作者:Brandon H. Bowser、Shu Wang、Tatiana B. Kouznetsova、Haley K. Beech、Bradley D. Olsen、Michael Rubinstein、Stephen L. Craig
DOI:10.1021/jacs.1c02149
日期:2021.4.7
sufficiently large (>3 nm per event) that individual unravelling events are resolved in both constant-velocity and constant-force single-molecule force spectroscopy (SMFS) experiments. Replacing a methylene in the pulling attachment with a phenyl group drops the force necessary to achieve rate constants of 1 s–1 from ca. 1970 pN (dialkyl handles) to 630 pN (diaryl handles), and the substituent effect is attributed
导致聚合物轮廓长度增加的机械化学反应有可能作为结构蛋白中非共价“存储长度”结构域机械展开的共价合成模拟物。在这里,我们报告了基于顺式-1,2-取代的环丁烷机械团的共价域聚合物家族中存储长度释放的力依赖性动力学。存储长度由[ n 中稠环的大小 ( n )决定.2.0] 双环结构,并且它可以做得足够大(每个事件 > 3 nm),以便在恒速和恒力单分子力谱 (SMFS) 实验中解决单个解开事件。用苯基取代牵引附件中的亚甲基会降低实现 1 s –1速率常数所需的力来自约 1970 pN(二烷基手柄)到 630 pN(二芳基手柄),取代效应归因于电子稳定性和机械杠杆效应的结合。相比之下,动力学受到存储长度量变化的影响可以忽略不计。解散力和伸展的独立控制有望作为聚合物网络中分子行为的探针和优化由共价域聚合物制成的材料的行为。
Preparation of both enantiomers of a synthon for novel nucleoside analogs by enzymatic desymmetrization of a meso-diol with a methylene cyclopropane skeleton
The enzymaticdesymmetrization of methylenecyclopropane diol or its corresponding diacetate derivative, generated from a [2+1] cycloaddition between dioxepin and methylchlorocarbene, is described. After screening five commercial lipases, the two enantiomers of acetic acid 2-hydroxymethyl-3-methylene-cyclopropylmethyl ester are obtained in high yields and excellent enantioselectivities by using PFL
First syntheticattemptstowards the so-far-unknown calicene (=5-(cycloprop-2-en-1-ylidene)cyclopenta-1,3-diene) precursors 3-(cyclopenta-2,4-dien-1-ylidene)tricyclo[3.2.2.22,4]nona-6,8-diene (4; Scheme 1), 1,4-di(cyclopenta-2,4-dien-1-ylidene)cyclohexa-2,5-diene (5; Scheme 2), and (2-bromocycloprop-1-en-1-yl)cyclopentadiene (6; X=Br; Scheme 5) are reported, which would represent very attractive compounds