Selective Generation of Free Radicals from Epoxides Using a Transition-Metal Radical. A Powerful New Tool for Organic Synthesis
作者:T. V. RajanBabu、William A. Nugent
DOI:10.1021/ja00082a021
日期:1994.2
halogens provides a route to functionalized cyclopentanes and other useful products. The radical initially formed from an epoxide can also be trapped by H-atom donors such as 1,4- cyclohexadiene or tert-butyl thiol, resulting in an overall reduction of the epoxide. In the absence of a H-atom donor or an olefin, this radical is trapped by Ti(", resulting in a fl-oxido-Ti organometallic species which undergoes
The substratespectrum of the inverting alkylsulfatase Pisa1 was investigated using a range of sec‐alkyl sulfate esters bearing aromatic, olefinic and acetylenic moieties. Perfect enantioselectivities were obtained for substrates bearing groups of different size adjacent to the sulfate ester moiety. Insufficient selectivities could be doubled by using dimethyl sulfoxide (DMSO) as co‐solvent. Hydrolytically
The first asymmetrictotalsynthesis of the unnatural enantiomer of cytotoxic awajanomycin (1) is reported. The synthetic approach features first a convergent strategy using the cross-olefin metathesis reaction to link the lipid side chain 2 and the piperidinone core structure 3. The second feature of the synthesis resides on the construction of segment 3 from the building block 5 via a three-component
A General Asymmetric Synthesis of (R)-Matsutakeol and Flavored Analogs
作者:Jia Liu、Honglian Li、Chao Zheng、Shichao Lu、Xianru Guo、Xinming Yin、Risong Na、Bin Yu、Min Wang
DOI:10.3390/molecules22030364
日期:——
and practical syntheticroute toward chiral matsutakeol and analogs was developed by asymmetric addition of terminal alkyne to aldehydes. (R)-matsutakeol and other flavored substances were feasibly synthesized from various alkylaldehydes in high yield (up to 49.5%, in three steps) and excellent enantiomeric excess (up to >99%). The protocols may serve as an alternative asymmetric synthetic method for
Total Synthesis of Polyrhacitides A and B by Use of an Iterative Strategy for the Stereoselective Synthesis of 1,3-Polyol Arrays
作者:Helge Menz、Stefan F. Kirsch
DOI:10.1021/ol902135v
日期:2009.12.17
The first total syntheses of polyrhacitides A and B, secondary metabolites from Chinese medicinal ants, were accomplished via an iterative approach to the 1,3-polyol motif. For the construction of all stereogenic centers, the catalytic asymmetric Overman esterification was utilized.