排序方式: 共有48条查询结果,搜索用时 15 毫秒
41.
Synthesis of the polyoxygenated nonalactone ring of 2-epibotcinolide was achieved using a highly stereoselective aldol reaction of the titanium enolate from a lactate-derived chiral ketone, a stereoselective dihydroxylation and a Yamaguchi macrolactonization reaction. 相似文献
42.
A stereoselective total synthesis of leiocarpin C ( 2 ) and (+)‐Goniodiol ( 1 ) by applying olefin cross‐metathesis and substrate directed dihydroxylation as the key steps is reported (Scheme 3). 相似文献
43.
A concise and efficient synthesis of (6R,7S,8R,8aS)-6,7,8-trihydroxyindolizidine (1-deoxy-7,8a-di-epi-castanospermine) 2 is described. The synthesis employs cross metathesis in building the key intermediate 9 and is used effectively in constructing indolizidine skeleton for the total synthesis of 1-deoxy-7,8a-di-epi-castanospermine and also for the bicyclic framework of pumiliotoxin 251D 12, 13. The indolizidine skeleton is achieved in one pot sequence of transformations such as deprotection of Cbz group, reduction of double bond, and cyclization. The configurational and conformational structures of compound 10 are unambiguously confirmed by X-ray analysis. 相似文献
44.
The enantioselective synthesis of oxylipin-3 has been carried out. The synthetic strategy was started from commercially available n-decanal. The chiral source was based on Sharpless asymmetric dihydroxylation and CBS reduction. 相似文献
45.
Kuladip Sarma 《Tetrahedron letters》2007,48(38):6776-6778
The combined advantages of using an enzyme immobilized lipase from Pseudomonas sp [PSLG6], hydrogen peroxide, ethyl acetate and microwave irradiation for the dihydroxylation of olefins are reported. 相似文献
46.
Yoann Marsac Stéphanie Legoupy Muriel Pipelier Anne-Marie Aubertin Rachid Benhida 《Tetrahedron》2005,61(32):7607-7612
Enantiomerically enriched cyclobutene compounds 13 and 24 are good precursors of several cyclobutane nucleoside analogs. The synthetic ways involve, in the key step, either hydroboration or dihydroxylation. 相似文献
47.
An efficient and straightforward stereoselective synthesis of α,β-unsaturated lactone (1) cleistenolide is described. The synthesis was started from commercially available d-tartaric acid and completed within 13 steps with an overall yield of 7.92%. The cis-olefin was generated from Still–Gennari protocol and one of the hydroxyl groups was from dihydroxylation methodology. All the reactions were very clean and the products were obtained in very good yields. 相似文献
48.
Charlotte Hampton Dr. Marco Simonetti Prof. Daniele Leonori 《Angewandte Chemie (International ed. in English)》2023,62(8):e202214508
Vicinal diols are abundant among natural and synthetic molecules, and also represent valuable intermediates throughout organic synthesis. Olefin dihydroxylation is an effective strategy to access these derivatives owing to the broad range and availability of alkene feedstocks. OsO4 is among the most used reagents to achieve this transformation, yet its high toxicity and cost remain concerning. Herein, we present a mechanistically distinct strategy for olefin dihydroxylation using nitroarenes as photoresponsive oxidants. Upon purple LEDs irradiation, these species undergo a [3+2]-photocycloaddition with a wide range of olefins to give stable 1,3,2-dioxazolidine intermediates. These species can be accumulated in solution and then reduced in situ to the desired diols, utilising readily accessible and easy to handle solid reagents as H2 surrogates. 相似文献