carbenes - 2025 ACF Nationals

Bonus

These molecules can be generated when a geminal dihalide exposed to organolithiums undergoes metal–halogen exchange, followed by an elimination. For 10 points each:

[10e] Name this class of molecules characterized by a carbon with an empty p orbital and six valence electrons instead of eight, meaning they have a lone pair and two covalent bonds instead of four bonds.

ANSWER: carbenes

[10m] Carbenes are used prominently in this reaction, whose Furukawa modification exchanges a zinc–copper carbene for diethylzinc. An organozinc carbenoid reacts with an alkene to form cyclopropane in this reaction.

ANSWER: Simmons–Smith reaction [prompt on cyclopropanation]

[10h] Abnormal N-heterocyclic carbenes often exhibit this property, in which positive and negative charges are delocalized around a core. Carbenes with this property do not possess a Wanzlick equilibrium.

ANSWER: mesoionic

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Conversion

Team	Opponent	Part 1	Part 2	Total	Parts
Columbia A	WUSTL B	10	10	20	EM
Cornell A	Ottawa	10	10	20	EM
Illinois B	Florida	0	0	0
Iowa State	Indiana	0	0	0
Johns Hopkins	Georgia State	10	10	20	EM
LSE	Vanderbilt	0	0	0
Maryland	Harvard	0	0	0
Minnesota	Michigan	10	0	10	E
NYU	Penn State	10	0	10	E
North Carolina A	Waterloo A	10	0	10	E
North Carolina B	Texas	0	0	0
Northwestern	Stanford	10	10	20	EM
RIT	Toronto C	10	0	10	E
Toronto A	Georgia Tech	10	10	20	EM
UCF	Ohio State	0	10	10	M
Virginia	Illinois A	0	0	0
WUSTL A	MIT	10	10	20	EM
Waterloo B	Arizona State	0	10	10	M
Winona State	Toronto B	0	0	0
Yale	Cornell B	0	0	0

Summary

Tournament	Exact Match?	Heard	PPB	Easy %	Medium %	Hard %
2025 ACF Nationals	Yes	20	9.00	50%	40%	0%