Xavier Ginesta

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[reaction: see text] An enantioselective preparation of the four diastereomeric 3-amino-2,3,6-trideoxy-hexoses, key components of anthracycline antibiotics, has been developed. Sharpless catalytic asymmetric epoxidation of the (2E)-2,5-hexadien-1-ol, regioselective ring opening with azide, followed by convenient functional group transformations, afforded(More)
A new finite-state vector quantization (FSVQ) algorithm is developed based on state space optimization and the derailment prevention requirement. The proposed derailment-free FSVQ (DF-FSVQ) achieves good performance through (i) state space reduction, which allows a practical implementation of high-order FSVQ, and (ii) derailment free state transitions.(More)
The reactions of aryl-stabilized sulfur ylides with organoboranes has been studied under a variety of conditions. At 5 or -78 degrees C, the reaction with Et3B gave a mixture of the first and second homologation products, but at -100 degrees C, only the first homologation product was obtained even with just 1.1 equiv of Et3B. Under these optimized(More)
We propose a new approach for text compression where fast decoding is more desirable than encoding. An example of such a requirement is information retrieval system. For efficient compression, high-order conditional probability information of text data is analyzed and modeled by utilizing vector quantization concept. Generally, vector quantization (VQ) has(More)
Subband image coding is one of the most efficient image compression techniques known to date. Its advantages over standard techniques based on transform coding are particularly important at very low bit rates. Tbe ability offered by a multiresolution decomposition approach to separately quantize the information contained in different frequency bands of an(More)
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