3,7,9-Triheterabicyclo[3.3.2]decan-10-ones: an unusual family of heterocycles obtained from 3,7-diheterabicyclo[3.3.1]nonan-9-ones
作者:Gregory L. Garrison、K. Darrell Berlin、Benjamin J. Scherlag、Ralph Lazzara、Eugene Patterson、Subbiah Sangiah、Chun Lin Chen、F. Schubot、Jintana Siripitayananon
DOI:10.1021/jo00079a009
日期:1993.12
A series of new 3,7,9-triheterabicyclo[3.3.2]decan-10-ones is reported for the first time. Members of the family of 3,7-diheterabicyclo[3.3.1]nonan-9-ones served as precursors of the title compounds. Spectral evidence suggests the 3,7,9-triheterabicyclo[3.3.2]decan-10-ones exist in a chair-boat (CB) reversible boat-chair (BC) equilibrium in solution. It is speculated that steric hindrance around the carbonyl group and possibly the variance in conformation BC versus CC of the individual 3,7-diheterabicydo-[3.3.1]nonan-9-one precursors in solution may influence the ease of oxygen and nitrogen insertion in the ring enlargement to give the title molecules. Confirmation that three members of the bicyclo[3.3.2] decan-10-ones exist in BC forms in the solid state was achieved via single crystal X-ray diffraction analysis for 7-benzyl-3-thia-7,9-diazabicyclo[3.3.2]decan-10-one (4a), 3,7-dibenzyl-3,7,9-triazabicyclo-[3.3.2]decan-10-one (4c), and 3,7-dibenzyl-9-oxa-3,7-diazabicyclo[3.3.2]decan-10-one (4d).