We tend to rely on expert authors to be … experts. But even experts are human beings so, to be fair, we must expect an occasional “expert” mistake. I want you to take a close look at some of the structural formulas in Paper 5 (OL, 2007, 9(22), 4653) and see if any mistakes have been made. I’m not promising that there are any. You will have to decide for yourself.

  • First, examine formulas 9, 10 and 7 in Scheme 1. If the transition state geometry is really the one shown in 9, will 10 and 7 be obtained? If the Scheme contains geometrical inconsistencies, accept the stereochemistry of 7 as correct and work backwards. What should 10 look like? What should 9 look like?
  • Second, examine the formulas of 13 and 14 in Scheme 2. This transformation is more complicated because 13 contains a chiral center. Draw a chair transition state that is consistent with this transformation.  Can 9 account for this transformation?

Due Monday. Suggestion: if you are having trouble visualizing these structures, use models. You should be able to figure out how to build a basic Claisen transition state using SPARTAN and you can decorate it from there.

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