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Biotin has been converted to 2-(biotinylamido)ethanol and condensed to phosphorylated oligonucleotides in a solid phase synthesis. The 5'-biotinylated oligonucleotides were enzymatically coupled to other DNA fragments by T4 DNA ligase or T4 RNA ligase. The hybridization properties of such biotin-labeled oligonucleotide probes were studied.

A rapid solid phase method of oligonucleotide synthesis based on monomeric protected nucleosides has been developed.

The deprotonation of several alkyl aryl selenides with lithium amide bases has been studied. The kinetic acidity of methyl m-trifluoromethylphenyl selenide was found to be 1/3.8 that of the sulfur analogue. The introduction of a m-trifluoromethyl substituent into methyl phenyl sulfide increased the kinetic acidity by a factor of 22.4. A variety of /3-hydroxy selenides have been prepared by the reduction of -phenylseleno ketones and the addition of -lithio selenides (prepared by deprotonation of benzyl phenyl selenide, bis(phenylseleno)methane, methoxymethyl m-trifluoromethylphenyl selenide, and phenylselenoacetic acid, and by n-butyllithium cleavage of bis(phenylseleno)methane) to carbonyl compounds. These /3-hydroxy selenides are converted to olefins on treatment with methanesulfonyl chloride and triethylamine. This reductive elimination proceeds exclusively or predominantly with anti stereochemistry. Simple olefins, styrenes, cinnamic acids, vinyl ethers, and vinyl selenides have been prepared using this technique. Attempts to carry out the syn reductive elimination of /3-hydroxy selenox-

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