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Unformatted text preview: (1) (10 points total) The molecule shown below is a terpenoid natural product called salvileucalin A. Professor Tantillo has performed quantum chemical calculations on reactions that this molecule may undergo in Nature. (a) In the structure shown at the right, please identify each oxygen atom as part of an alcohol (also note whether it is primary, secondary or tertiary), an ether, a ketone, an aldehyde, an ester, or a carboxylic acid. (b) Please identify the hybridization a n d geometry of the three atoms marked with 's in part (a). * Chem 118A, Fall 2008, Midterm 1 _______________________________ name * * (2) (15 points total) Please rank the following 3 molecules in order of increasing basicity (1=least basic, 3 = most basic) and e x p l a i n y o u r r e a s o n i n g c l e a r l y a n d c o n c i s e l y . O O O O O H O * key ether sp 2 trigonal planar sp 3 tetrahedral ester ester ester ester sp 2 trigonal planar 3 2 1 The lefthand molecule is less basic than the middle molecule because its anionic lone pair is located in an sp 2 orbital rather than an sp 3 orbital. The sp 2 orbital has more s-character, which means that the electrons are closer to the nucleus and lower in energy. Since the electrons are "happier" they are less likely to react and abstract a proton.are less likely to react and abstract a proton....
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