Rich G. Carter

Low-surface-area hard carbon anode for na-ion batteries via graphene oxide as a dehydration agent.

Na-ion batteries are emerging as one of the most promising energy storage technologies, particularly for grid-level applications. Among anode candidate materials, hard carbon is very attractive due to its high capacity and low cost. However, hard carbon anodes often suffer a low first-cycle Coulombic efficiency and fast capacity fading. In this study, we discover that doping graphene oxide into sucrose, the precursor for hard carbon, can effectively reduce the specific surface area of hard carbon to as low as 5.4 m(2)/g. We further reveal that such doping can effectively prevent foaming during caramelization of sucrose and extend the pyrolysis burnoff of sucrose caramel over a wider temperature range. The obtained low-surface-area hard carbon greatly improves the first-cycle Coulombic efficiency from 74% to 83% and delivers a very stable cyclic life with 95% of capacity retention after 200 cycles.

Improved Protocol for Asymmetric, Intramolecular Heteroatom Michael Addition Using Organocatalysis: Enantioselective Syntheses of Homoproline, Pelletierine, and Homopipecolic Acid

An improved protocol for the construction of enantioenriched pyrrolidine, indoline, and piperidine rings using an organocatalyzed, intramolecular heteroatom Michael addition is described. Application to the enantioselective synthesis of homoproline, homopipecolic acid, and pelletierine has been accomplished.

Enantioselective Total Synthesis of Lycopodine

The first enantioselective total synthesis of lycopodine has been completed. Key steps include a highly diastereoselective organocatalyzed cyclization of a keto sulfone to establish the key C7 and C8 stereocenters and a tandem 1,3-sulfonyl shift/intramolecular Mannich cyclization to form the tricyclic core.

N-(p-Dodecylphenylsulfonyl)-2-pyrrolidinecarboxamide: A Practical Proline Mimetic for Facilitating Enantioselective Aldol Reactions

A highly practical and readily available proline surrogate has been developed with improved solubility properties in common, nonpolar organic solvents. This sulfonamide-based catalyst has proven highly effective at facilitating enantioselective and diastereoselective aldol reactions with a range of substrates in nonpolar organic solvents in the presence of a single equivalent of water. Additionally, catalyst loading as low as 2 mol % can be employed in the absence of any organic solvent with continued high levels of selectivity.

Synthesis of all-carbon, quaternary center-containing cyclohexenones through an organocatalyzed, multicomponent coupling.

Organocatalyzed multicomponent coupling using a new ester-containing, proline aryl sulfonamide has been developed for accessing densely functionalized cyclohexenones, each containing a quaternary center in high enantio- and diastereoselectivity. In contrast to most enamine/iminium-catalyzed reactions, the use of molecular sieves was critical to optimum enantioselectivity.

Development of an Enantioselective Route toward the Lycopodium Alkaloids: Total Synthesis of Lycopodine

Synthesis of a C(15)-desmethyl tricycle core of lycopodine has been accomplished. Key steps in the synthetic sequence include organocatalytic, intramolecular Michael addition of a keto sulfone and a tandem 1,3-sulfonyl shift/Mannich cyclization to construct the tricyclic core ring system. Synthetic work toward this natural product family led to the development of N-(p-dodecylphenylsulfonyl)-2-pyrrolidinecarboxamide, an organocatalyst which facilitates enantioselective, intramolecular Michael additions. A detailed mechanistic discussion is provided for both the intramolecular Michael addition and the sulfone rearrangement. Finally, the application of these discoveries to the enantioselective total synthesis of alkaloid lycopodine is described.

Studies on the synthesis of the core structures of the antitumor agents neocarzinostatin, kedarcidin, C-1027 and maduropeptin

Abstract The bicyclo[7.3.0]dodecadiyne core structure of the antitumor agents neocarzinostatin, kedarcidin, C-1027 and maduropeptin can be readily constructed by an intramolecular aldol reaction to form the C -8 C -9 bond only if the C-6,7 triple bond is complexed as its η 2 Co 2 (CO) 6 -acetylene adduct.

Studies on the Stereoselective Synthesis of the Marine Antitumor Agent Eleutherobin

Abstract (+)-Carvone has been converted into the sulfone 14 which comprises the left-hand side of the cytotoxic sesquiterpene, eleutherobin 1 . Julia coupling of 14 to the aldehyde 21 , followed by oxidation, dissolving metal reduction and stereoselective reduction of the C8 carbonyl group resulted in 29 , which has the correct stereochemistry at C8 and C9. Further conversion of 29 into 37 , and attempted intramolecular cyclization resulted in fragmentation to the furan 39 and 38 . Asymmetric epoxidation of the allylic alcohols 42 and 48 resulted in neighboring group participation from the adjacent dimethoxy acetal and formation of the rearranged oxepane derivatives 44 , 45 and 49 , respectively.

Total Synthesis of Cytotoxic Macrolide Amphidinolide B1 and the Proposed Structure of Amphidinolide B2

The first enantioselective total syntheses of cytotoxic macrolide amphidinolide B1 and the proposed structure for amphidinolide B2 have been accomplished. Key features of the syntheses include a diastereoselective aldol condensation, a spontaneous Wadsworth-Emmons macrocyclization and a directed epoxidation/elimination sequence.

Primary Amine, Thiourea-Based Dual Catalysis Motif for Synthesis of Stereogenic, All-Carbon Quaternary Center-Containing Cycloalkanones

The enantioselective synthesis of α,α-disubstituted cycloalkanones has been developed using a primary amine, thiourea-based dual catalysis pathway. A range of electrophiles and ring sizes are tolerated under the reaction conditions. A possible catalytic cycle is presented to explain the reactivity.