| In summary, a concise method for the preparation of diverse α-amino alcohols and α-amino acids in both enantiomeric series from readily available achiral starting materials has been developed. Included in the analogs is 4-methoxyhomophenylalanine, a compound of current interest. The precursor vinyl amino alcohols, and vinyl oxazolidines were obtained via lipase-catalyzed kinetic resolutions. Key in this convergent approach was Pd mediated Suzuki cross-coupling.; The vinyloxazolidines which were exploited in chapter 1 in the synthesis of amino acids were cross-coupled under Suzuki conditions to an advanced intermediate of cis-dihydrobromodiol. Through a series of transformations a variety of manno-azasugar amino acids and manno -azasugar amino alcohols were synthesized. Additionally a key advanced intermediate was transformed into a highly elaborated quinolizidine.; The chiral building blocks, vinylglycinols were additionally utilized for the synthesis of derivatives of trans-4-hydroxypipecolic acids. Key transformations include ring closing metathesis to construct the piperidine ring and the Prevost reaction to install the 4-hydroxy regio- and stereoselectively as determined by X-ray structure analysis. A key intermediate was used to synthesize the hydrochloride of the natural product (−)-SS20846A.; N-Tosyl-N-benzylvinylglycinol was utilized in the synthesis of advanced intermediates which constituted formal syntheses of the natural products 1-Deoxymannojirimycin and (+)-swainsonine. |
