stereoselective - 2024 ACF Winter

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]

Back to bonuses

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%
2024 ACF Winter at Brandeis	2024-11-16	Y	10	17.00	100%	30%	40%

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
Bard A	Columbia B	0	0	10	10
Haverford A	Rowan A	10	0	10	20
Columbia A	Johns Hopkins A	10	10	10	30
Penn State B	Penn B	0	0	10	10
Penn State A	Penn A	0	0	10	10
Lehigh A	Rutgers C	0	0	0	0
Notre Dame	WashU D	0	0	10	10
UIUC B	Purdue A	0	0	10	10
Indiana B	Purdue D	0	0	0	0
SIUE A	UChicago B	0	10	10	20
UChicago D	UIUC D	0	10	10	20
UIUC A	Indiana A	0	0	10	10
UChicago A	UIUC C	0	0	10	10
WashU B	UChicago C	10	10	10	30
Northwestern A	WashU C	10	10	10	30
CWRU B (UG)	CWRU D (DII)	0	10	10	20
Michigan C (UG)	Kenyon B (DII)	0	0	10	10
CWRU A (UG)	Michigan State C (UG)	0	10	10	20
Ohio State B (DII)	Pitt B (UG)	0	0	10	10
Ohio State C (DII)	Michigan B	0	0	10	10
Pitt A	Michigan D	10	0	0	10
Michigan State B (UG)	Kenyon A (UG)	0	10	10	20
Arkansas	McGill E	0	0	10	10
NYU A	Central Oklahoma	0	0	10	10
Mississippi State	Vassar B	10	0	10	20
Texas B	Missouri	0	0	10	10
WUSTL A	Ole Miss	10	0	10	20
Texas A	NYU B	0	0	10	10
Texas C	Texas D	0	0	10	10
Vassar A	Oregon State	10	0	10	20
UBC A	UW B	10	10	10	30
Alberta	UBC B	0	0	0	0
UW A	SFU	10	0	10	20
Florida State University A	UCF B	0	0	10	10
UF B	UF A	10	10	10	30
UCF A	UF C	10	0	10	20
Florida Tech B	UF D	0	0	10	10
UF E	Florida Tech A	0	0	10	10
Oxford B	Birmingham	0	0	10	10
Imperial A	Bristol B	10	10	10	30
Cambridge B	Southampton B	0	10	10	20
Durham B	Cambridge D	0	10	10	20
Durham A	Edinburgh	0	0	10	10
Warwick B	Imperial B	0	0	10	10
Cambridge C	LSE B	10	0	10	20
LSE A	Southampton A	0	0	10	10
Southampton B	Southampton A	0	0	10	10
Oxford A	Team 1	10	10	10	30
Bristol A	Warwick A	0	10	10	20
A Brandeis Supreme	Boston University B	0	0	10	10
Amherst A	Williams A	0	0	10	10
Yale B	Bowdoin A	0	10	10	20
Carabrandeis	Brown A	0	0	10	10
Clark A	Bowdoin B	0	0	10	10
Diamond Brandeis	Boston University A	0	0	10	10
Harvard A	Brandeises Brew	10	10	10	30
MIT A	Northeastern A	10	10	10	30
Yale A	Tufts B	10	10	10	30
Yale C	Tufts A	0	0	10	10