Organic Synthesis Highlights

Mulzer, Johann; Altenbach, Hans‐Josef; Braun, Michael; Krohn, Karsten; Reissig, H.‐U.

doi:10.1002/9783527621385

Cited by 105 publications

(40 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1 However, despite spectacular successes in the development of highly enantioselective alkene dioxygenation protocols – principally epoxidation 2 and dihydroxylation 3 – the control of enantioselectivity in alkene halogenation has only recently begun to capture the imagination of the synthetic organic community. Whilst the field is undoubtedly still in its infancy, a variety of catalytic, enantioselective olefin difunctionalization reactions involving all four (common) halogens have now been realized, and these transformations fall under the broad umbrella of “alkene halofunctionalization” reactions.…”

Section: Introduction: State Of the Artmentioning

confidence: 99%

Catalytic, Stereoselective Dihalogenation of Alkenes: Challenges and Opportunities

2015

View full text Add to dashboard Cite

Although recent years have witnessed significant advances in the development of catalytic, enantioselective halofunctionalizations of alkenes, the related dihalogenation of olefins to afford enantioenriched vicinal dihalide products remains comparatively underdeveloped. However, the growing number of complex natural products bearing halogen atoms at stereogenic centers has underscored this critical gap in the synthetic chemist's arsenal. This Review highlights the selectivity challenges inherent in the design of enantioselective dihalogenation processes, and formulates a mechanism-based classification of alkene dihalogenations, including those that may circumvent the "classical" haliranium (or alkene-dihalogen π-complex) intermediates. A variety of metal and main group halide reagents that have been used for the dichlorination or dibromination of alkenes are discussed, and the proposed mechanisms of these transformations are critically evaluated. AbstractCatalysis of alkene dihalogenation , under different activation modes, with control over both the absolute and relative stereochemical course of dihalogen addition, is one of the most vexing problems in stereoselective synthesis. Dihalogenations that circumvent the "classical" haliranium (or alkene-dihalogen π complex) intermediates provide new and exciting opportunities for catalysis, potentially having broader implications for the design of stereoselective alkene difunctionalizations.

show abstract

Section: Introduction: State Of the Artmentioning

confidence: 99%

Catalytic, Stereoselective Dihalogenation of Alkenes: Challenges and Opportunities

2015

View full text Add to dashboard Cite

show abstract

“…Although enzymes have been employed widely for biocatalytic resolutions, 18 little information exists regarding the enantioselective enzyme-catalyzed hydrolysis of racemic nucleosides. 19 Wengel and co-workers 20 reported the first use of esterase catalyzed diastereoselective deacetylation to solve the problem of nucleoside anomer separation.…”

Section: Resultsmentioning

confidence: 99%

Scaleable processes for the synthesis of (−)-β-d-2,6-diaminopurine dioxolane (Amdoxovir, DAPD) and (−)-β-d-2-aminopurine dioxolane (APD)

Zhou¹,

Coats²,

Zhang³

et al. 2012

Tetrahedron

View full text Add to dashboard Cite

An efficient and scalable synthesis of (−)-DAPD and (−)-APD has been developed. We discovered that t-butyl cyanoacetate can be used as a new additive for the sugar nucleoside base coupling step en route to DAPD with improved β-selectivity and an isolated yield four fold greater than the original process scale method. Using this new process, (−)-DAPD has been prepared on greater than 20 g scale. In the synthesis of (−)-APD, a key enzyme-catalyzed hydrolysis reaction afforded the water-soluble deprotected α-anomer while leaving the β-anomer completely untouched.

show abstract

“…In our first generation approach [48] en route to core fragment 131 we planned to use the INOC reaction [49] for an annulation of ring B to an already existing cyclohexene TMSCl ring A, which should be derived from quinic acid. In this way, we hoped that the existing chiral centers in quinic acid could control the construction of the remaining stereogenic centers.…”

Section: Synthesis Of Branimycinmentioning

confidence: 99%