Packet 8: Bonus 14
One reactant in the Mannich reaction undergoes this process before attacking the iminium ion. For 10 points each:
[10h] Name this process that is accelerated in acidic conditions via the formation of an oxonium ion intermediate.
ANSWER: keto–enol tautomerization [accept tautomerization between enols and ketones; accept carbonyls or aldehydes in place of “ketones”; prompt on descriptions of interconversion between ketones and enols; prompt on tautomerization by asking “between what two species?”]
[10m] As a consequence of the keto tautomer being favored in equilibrium, acid-catalyzed hydration of these species via an oxymercuration reaction yields ketones rather than enols.
ANSWER: alkynes [reject “alkanes” or “alkenes”]
[10e] The keto tautomer is generally favored over the enol tautomer since it has this type of bond with a higher bond energy than the enol’s carbon–carbon double bond. Carbonyls possess this type of bond.
ANSWER: CO double bonds [or carbon–oxygen double bonds; prompt on carbon–oxygen bonds or double bonds]
<Stanford A, Chemistry> | H. Prelims 8 - Stanford A + Georgia Tech C + Columbia A + Columbia B
| Heard | PPB | E % | M % | H % |
|---|---|---|---|---|
| 20 | 10.50 | 80% | 20% | 5% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| Brown | UC Berkeley B | 0 | 0 | 10 | 10 | E |
| Cambridge | British Columbia | 0 | 0 | 10 | 10 | E |
| Chicago A | WashU | 0 | 0 | 10 | 10 | E |
| Georgetown | Swarthmore | 0 | 0 | 0 | 0 | |
| Harvard | Ohio State | 0 | 10 | 10 | 20 | ME |
| Illinois A | Stanford B | 0 | 0 | 10 | 10 | E |
| Illinois B | Chicago B | 0 | 0 | 10 | 10 | E |
| MIT | Pittsburgh | 0 | 10 | 10 | 20 | ME |
| Maryland A | NYU B | 0 | 0 | 0 | 0 | |
| Maryland B | UCLA | 10 | 0 | 10 | 20 | HE |
| Michigan | Bruin | 0 | 0 | 10 | 10 | E |
| Purdue | Minnesota | 0 | 10 | 10 | 20 | ME |
| Rutgers | North Carolina | 0 | 10 | 10 | 20 | ME |
| Texas | Georgia Tech A | 0 | 0 | 0 | 0 | |
| Toronto A | Georgia Tech B | 0 | 0 | 10 | 10 | E |
| Toronto B | Northwestern A | 0 | 0 | 10 | 10 | E |
| Vanderbilt | Northwestern B | 0 | 0 | 0 | 0 | |
| Virginia | UC Berkeley A | 0 | 0 | 10 | 10 | E |
| Virginia Tech | Penn State | 0 | 0 | 10 | 10 | E |
| Waterloo | Indiana | 0 | 0 | 10 | 10 | E |
Summary
| Tournament | Edition | Match | Heard | PPB | E % | M % | H % |
|---|---|---|---|---|---|---|---|
| Main Site | 2026-04-17 | ✓ | 20 | 10.50 | 80% | 20% | 5% |