Question
Cram’s rule describes the conditions in which this property can be “induced” in additions. For 10 points each:
[10m] Name this property of reactions which preferentially form one of the R or S isomers. The degree of this property is often measured as a quantity abbreviated “ee” (“E-E”), and it results in a nonzero optical activity.
ANSWER: stereoselective [or enantioselective; or asymmetric; or word forms; accept stereospecific; prompt on chiral or selective]
[10h] In Cram’s original experiment, 1,2-diphenyl-1-propanone (“one two die-FEEN-ul one PRO-puh-known”) reacted with this compound, which produced the erythro isomer. This very powerful reducing agent named for two metals is stronger than sodium borohydride.
ANSWER: lithium aluminum hydride [or LAH; or LiAlH4]
[10e] Conversely, when Cram used a benzene substituted with this element to produce the same product, it favored the threo isomer. This halogen is uniquely a reddish-brown liquid at room temperature.
ANSWER: bromine [or Br]
<Chemistry>
Summary
| 2024 ACF Winter at UC Berkeley | 2024-11-16 | Y | 3 | 10.00 | 67% | 33% | 0% |
| 2024 ACF Winter at Lehigh | 2024-11-16 | Y | 6 | 13.33 | 83% | 33% | 17% |
| 2024 ACF Winter at Northwestern | 2024-11-16 | Y | 9 | 15.56 | 89% | 22% | 44% |
| 2024 ACF Winter at Ohio State | 2024-11-16 | Y | 7 | 14.29 | 86% | 14% | 43% |
| 2024 ACF Winter at Online | 2024-11-16 | Y | 8 | 13.75 | 100% | 38% | 0% |
| 2024 ACF Winter at UBC | 2024-11-16 | Y | 3 | 16.67 | 67% | 67% | 33% |
| 2024 ACF Winter at Central Florida | 2024-11-16 | Y | 5 | 16.00 | 100% | 40% | 20% |
| 2024 ACF Winter at Oxford | 2024-11-16 | Y | 11 | 17.27 | 100% | 27% | 46% |
Data
| Berkeley C | Berkeley A | 0 | 0 | 10 | 10 |
| Stanford A | Berkeley B | 0 | 0 | 0 | 0 |
| Stanford M | Stanford L | 10 | 0 | 10 | 20 |