1,3-cyclobutadiene - 2025 ACF Winter

Question

Answer the following about molecular containers, which can stabilize unfavourable transition states, for 10 points each.

[10h] Carcerands are completely closed molecular containers and were first used to mediate the synthesis of this highly unstable molecule. This is the lightest antiaromatic molecule, and can dimerize to form Dewar benzene.

ANSWER: 1,3-cyclobutadiene [or [4]annulene; or cyclobuta-1,3-diene]

[10m] Another molecular container, cucurbituril, has been used to carry out a catalysis-resistant one of these reactions. This reaction creates a 6-membered ring and usually forms the endo product.

ANSWER: Diels–Alder reaction [or DA reaction]

[10e] Molecular containers often accelerate this quantity, which is how fast a reaction proceeds. Catalysts often increase this quantity, which is calculated using a constant denoted lowercase k.

ANSWER: reaction rate [reject “rate constant” or “reaction rate constant”]

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Summary


California	Main	Y	5	16.00	100%	60%	0%
Canada	Main	Y	1	30.00	100%	100%	100%
Florida	Main	Y	13	15.38	92%	39%	23%
Great Lakes	Main	Y	6	11.67	83%	33%	0%
Lower Mid-Atlantic	Main	Y	7	11.43	100%	14%	0%
Midwest	Main	Y	10	15.00	90%	40%	20%
North	Main	Y	10	15.00	90%	50%	10%
Northeast	Main	Y	5	16.00	100%	20%	40%
Overflow	Main	Y	4	12.50	100%	25%	0%
Pacific Northwest	Main	Y	12	16.67	92%	58%	17%
South Central	Main	Y	5	10.00	80%	20%	0%
Southeast	Main	Y	12	14.17	100%	33%	8%
UK	Main	Y	4	12.50	100%	25%	0%
Upper Mid-Atlantic	Main	Y	8	16.25	100%	38%	25%
Upstate NY	Main	Y	8	16.25	100%	50%	13%
2025 ACF Nationals	2025-08-09	Y	14	16.43	93%	43%	29%
2024 ARCADIA at UC Berkeley	04/19/2025	Y	4	7.50	75%	0%	0%

Data


Berkeley C	UCSC	0	10	10	20
Berkeley B	Stanford C	0	0	10	10
Berkeley E	Stanford B	0	10	10	20
Berkeley A	Berkeley F	0	0	10	10
UCLA A	UCLA D	10	10	10	30
Stanford A	Berkeley D	0	10	10	20
Queen's B	Guelph B	0	0	10	10
Melbourne B	ERAU B	0	0	10	10
FIU	UCF B	0	0	0	0
UF B	FSU	0	0	10	10
UF C	Melbourne A	0	10	10	20
UCF A	UF D	0	10	10	20
ERAU A	USF	0	0	10	10
Toronto E	McMaster B	0	0	10	10
Toronto H	McMaster C	0	0	10	10
Carleton	Queen's A	0	10	10	20
Toronto A	Toronto D	10	10	10	30
Toronto B	Ottawa	10	10	10	30
McGill A	Toronto C	0	10	10	20
Toronto J	Toronto F	0	0	10	10
Toronto K	Toronto I	0	0	10	10
Toronto G	Toronto Metropolitan	0	0	10	10
Western Ontario	Waterloo	0	0	0	0
McGill B	McGill C	0	0	10	10
OSU C	Pitt B	0	10	10	20
OSU D	Pitt A	0	0	10	10
CWRU D	CWRU B	0	0	10	10
Pitt C	CWRU C	0	0	10	10
MSU A	Kenyon A	0	0	10	10
CWRU A	OSU A	0	0	10	10
OSU B	Kenyon B	0	0	10	10
McMaster A	Guelph A	10	10	10	30
North Carolina B	Clemson A	10	10	10	30
NC State	Clemson B	0	0	10	10
North Carolina C	James Madison	0	0	10	10
Tusculum	North Carolina A	0	0	10	10
Liberty C	Roanoke	0	0	0	0
Liberty B	South Carolina B	0	0	10	10
Virginia Tech B	Tennessee A	10	10	10	30
Virginia Tech A	Tennessee B	0	10	10	20
Virginia A	South Carolina A	0	10	10	20
Liberty A	Virginia B	0	0	10	10
George Mason B	Catholic University	0	0	10	10
George Mason A	Notre Dame E	0	10	10	20
Johns Hopkins A	Georgetown B	0	10	10	20
Johns Hopkins B	Johns Hopkins C	0	10	10	20
Maryland A	Maryland C	0	10	10	20
UMBC A	Maryland D	0	0	10	10
NYU A	VCU A	10	0	10	20
Penn A	NYU B	0	10	10	20
George Washington B	George Mason C	0	0	0	0
Swarthmore A	Columbia A	0	0	10	10
Columbia B	Rutgers C	10	10	10	30
Rutgers B	Columbia C	10	0	10	20
Rowan A	Princeton A	0	0	10	10
Vassar A	Lehigh B	0	0	10	10
Georgetown A	George Washington A	0	0	10	10
Missouri B	SIUE	0	0	10	10
WashU D	Truman State	0	0	10	10
WashU C	WashU A	0	0	10	10
Missouri A	William Woods	0	10	10	20
Chicago B	Chicago C	10	10	10	30
Chicago D	Illinois B	0	10	10	20
Illinois A	UIC	0	10	10	20
Michigan B	Indiana A	0	10	10	20
Illinois C	Kentucky	0	0	10	10
Michigan C	Indiana B	0	10	0	10
Chicago A	Notre Dame A	10	0	10	20
Notre Dame C	Notre Dame B	0	0	10	10
Louisville A	Notre Dame D	0	10	10	20
Michigan A	Purdue A	0	10	10	20
Michigan D	Purdue B	0	0	10	10
Louisville B	Purdue C	0	0	10	10
Carleton	Iowa State	0	0	10	10
Minnesota B	Macalester B	0	0	0	0
Minnesota C	St. Thomas	0	10	10	20
Nebraska	Minnesota A	0	0	10	10
Wisconsin	Macalester A	0	0	10	10
BC A	Amherst B	0	0	10	10
Amherst A	BC B	0	0	10	10
BU	MIT A	0	0	10	10
Brown C	Bowdoin A	0	0	10	10
Tufts A	Brandeis Clemenceau	0	0	10	10
Bowdoin B	Brandeis Orlando	0	0	10	10
Dartmouth	Brandeis Wilson	0	10	10	20
Brown A	Yale A	0	0	10	10
Brown B	Cornell-UG	0	0	10	10
Harvard	Tufts B	10	10	10	30
Williams	Brandeis Lloyd George	0	10	10	20
Yale B	MIT B	0	10	10	20
Alberta	British Columbia C	0	0	10	10
British Columbia A	Washington A	0	0	10	10
British Columbia B	Washington B	0	0	10	10
Simon Fraser	British Columbia D	0	10	10	20
Northwestern C	Arizona State A	0	0	10	10
Alberta B	Northwestern B	0	0	10	10
McGill D	Rose State	0	0	10	10
Texas A	Northwestern A	10	10	10	30
Texas B	Tulsa	10	0	10	20
UCO	Iowa	0	10	10	20
UTD A	Ohio	0	10	10	20
UTD B	Arizona State B	0	0	10	10
Alabama A	Huntsville B	0	0	10	10
Georgia Tech C	Georgia Tech B	0	0	10	10
Mississippi State A	Vanderbilt A	0	0	10	10
Alabama B	Sewanee A	10	10	10	30
UAB A	Georgia Tech A	0	10	10	20
Bruin A	Vanderbilt B	0	0	10	10
Auburn A	Huntsville A	0	10	10	20
Georgia Tech D	Auburn B	0	10	10	20
Oxford B	Cambridge B	0	0	10	10
Warwick A	Birmingham A	0	10	10	20
Oxford A	Bristol A	0	10	10	20
Bristol B	City St George's A	0	0	10	10
Durham B	Sheffield C	0	0	10	10
Cambridge C	Edinburgh A	10	10	10	30
Edinburgh B	Sheffield B	0	0	10	10
Imperial A	LSE A	10	10	10	30
Imperial B	Imperial C	0	10	10	20
Manchester A	Sheffield A	0	0	0	0
Cambridge D	Manchester B	10	10	10	30
Cambridge A	Southampton A	10	0	10	20
LSE B	Southampton B	0	0	10	10
Binghamton A	Binghamton B	0	0	10	10
Syracuse	Cornell-DII	0	0	0	0
RIT A	ESF	0	0	10	10
RIT B	Rochester	0	0	10	10
Warwick B	Durham A	0	0	10	10