Even eight-memberedrings (such as in 2) can be formed by ring-closingmetathesis of glucose derivatives such as 1. Enantiomerically pure tricyclic spiro compounds can also be prepared.
The Copper(I) Catalysed [2 + 2] Intramolecular Photoannulation of Carbohydrate Derivatives
作者:David J. Holt、William D. Barker、Paul R. Jenkins、Subrata Ghosh、David R. Russell、John Fawcett
DOI:10.1055/s-1999-3120
日期:——
Carbohydrate derivatives 1a, 1b, 3a and 3b have been subjected to copper(I) catalysed photoannulation to produce tetracyclic products 2a, 2b, 4a and 4b respectively as single enantiomers. The same reaction carried out on substrates 5a and 5b leads stereoselectively to the spiro products 6a and 6b respectively. Photoannulation of substrate 7 gave an approximate 1 : 1 mixture of spiro products 8 and 9. A mechanistic rationalisation of these results is proposed.
Stereoselective Preparation of Enantiomerically Pure Annulated Carbohydrates Using Ring-Closing Metathesis
作者:David J. Holt、William D. Barker、Paul R. Jenkins、Jagannath Panda、Subrata Ghosh
DOI:10.1021/jo991392z
日期:2000.1.1
Ring-closing metathesis has been applied to a series of glucose derivatives to produce cyclopentene derivatives 5a and 5b, cyclohexene derivatives 8 and 9, cycloheptene 12, and cyclooctene 14. Spirocyclic dihydrofurans 19, 26a, and 26b, along with dihydropyran 22, were also produced. A range of fused oxepine derivatives 29a-c and one oxo-cyclononene 31 were also prepared. Cyclopentene 5b was subjected
The synthesis of fused and spiro annulated carbohydrate structures using copper(i) catalysed intramolecular photoannulation of glucose derivativesElectronic supplementary information (ESI) available: NMR data and ORTEP diagrams. See http://www.rsc.org/suppdata/ob/b3/b315623k/
作者:David J. Holt、William D. Barker、Subrata Ghosh、Paul R. Jenkins
DOI:10.1039/b315623k
日期:——
catalysed by copper(i)triflate has been applied to a series of carbohydrate derivatives obtained from glucose. Dienes 1a and 1b lead to cyclobutanes 3a and 3b whereas the diastereoisomeric dienes 5a and 5b gave diastereoisomeric products 7a and 7b. These results demonstrate that the reaction is stereospecific. Products 3a and 7a were converted into bromoesters 4 and 9 respectively. The Vasella elimination