A compound of Formula I: or a pharmaceutically acceptable salt, or solvate thereof, wherein: G is R 1 or a hydroxyl protecting group PG; R 1 is hydrogen, alkyl, alkenyl, alkynyl, (cycloalkyl)alkyl, (heterocyclo)alkyl, arylalkyl, or heteroarylalkyl, wherein the cycloalkyl, heterocyclo, aryl, and heteroaryl portions thereof are optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; R 2 is (a) hydrogen, cyano, carboxy, alkoxycarbonyl, or carboxamido; or (b) alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, (cycloalkyl)alkyl, (cycloalkenyl)alkyl, (heterocyclo)alkyl, arylalkyl, heteroarylalkyl, (arylalkoxy)carbonyl, or (heteroarylalkoxy)carbonyl, any of which is optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; R 3 and R 4 are each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, (cycloalkyl)alkyl, (cycloalkenyl)alkyl, (heterocyclo)alkyl, arylalkyl, and heteroarylalkyl, wherein any of which, when other than hydrogen, is optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; R 5 is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, (cycloalkyl)alkyl, (cycloalkenyl)alkyl, (heterocyclo)alkyl, arylalkyl, and heteroarylalkyl, wherein any of which, when other than hydrogen, is optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; and is a single bond or a double bond. G is R 1 or a hydroxyl protecting group PG; R 1 is hydrogen, alkyl, alkenyl, alkynyl, (cycloalkyl)alkyl, (heterocyclo)alkyl, arylalkyl, or heteroarylalkyl, wherein the cycloalkyl, heterocyclo, aryl, and heteroaryl portions thereof are optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; R 2 is (a) hydrogen, cyano, carboxy, alkoxycarbonyl, or carboxamido; or (b) alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, (cycloalkyl)alkyl, (cycloalkenyl)alkyl, (heterocyclo)alkyl, arylalkyl, heteroarylalkyl, (arylalkoxy)carbonyl, or (heteroarylalkoxy)carbonyl, any of which is optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; (a) hydrogen, cyano, carboxy, alkoxycarbonyl, or carboxamido; or (b) alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, (cycloalkyl)alkyl, (cycloalkenyl)alkyl, (heterocyclo)alkyl, arylalkyl, heteroarylalkyl, (arylalkoxy)carbonyl, or (heteroarylalkoxy)carbonyl, any of which is optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; R 3 and R 4 are each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, (cycloalkyl)alkyl, (cycloalkenyl)alkyl, (heterocyclo)alkyl, arylalkyl, and heteroarylalkyl, wherein any of which, when other than hydrogen, is optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; R 5 is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, (cycloalkyl)alkyl, (cycloalkenyl)alkyl, (heterocyclo)alkyl, arylalkyl, and heteroarylalkyl, wherein any of which, when other than hydrogen, is optionally substituted with 1, 2, or 3 substituents, each independently selected from the group consisting of hydroxy, halo, haloalkyl, amino, alkylamino, dialkylamino, carboxy, and alkoxycarbonyl; and is a single bond or a double bond.