Silanes, continued allyl

Amino acids continue to be useful starting materials for the preparation of enantiomerically-pure heterocycles. Henk Hiemstr a of the University of Amsterdam and Floris Rutjes of the Univer sity of Nijmegen report (J. Am. Chem. Soc. 2004, 126,4100) that cyclization of the allyl silane 9 followed by ring-closing metathesis leads to the highly-functionalized quinolizidine 11. 

The Claisen rearrangement of ester enolates continues to provide interesting syntheses of unsaturated acids. Rearrangement of the ester (32) leads to the allyl silane (33) in 61 and 53% yield for two examples protiodesilylation then provides the Se-unsaturated acids (34) in quantitative and 85 % yield, with a ratio of >8 1 of the diastereoisomers when = H and R = Me (Scheme 17). ... 

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