Enantioselective Synthesis of Succinimides by Michael Addition of 1,3-Dicarbonyl Compounds to Maleimides Catalyzed by a Chiral Bis(2-aminobenzimidazole) Organocatalyst

A wide variety of chiral succinimides have been prepared in high yields and enantioselectivities by asymmetric conjugate addition of 1,3-dicarbonyl compounds to maleimides under very mild reaction conditions using a bifunctional benzimidazole-derived organocatalyst. Computational and NMR studies support the hydrogen-bonding activation role of the catalyst and the origin of the stereoselectivity of the process.

Solvent-dependent enantioswitching in the Michael addition of α,α-disubstituted aldehydes to maleimides organocatalyzed by mono-N-Boc-protected cyclohexa-1,2-diamines

Enantiomerically pure mono-N-Boc-protected trans-cyclohexa-1,2-diamines are used as organocatalysts for the enantioselective conjugate addition of α,α-disubstituted aldehydes to maleimides. Using a single enantiomer of the organocatalyst, both enantiomeric forms of the resulting Michael adducts bearing a new quaternary stereocenter are obtained in high yields, by only changing the reaction solvent from chloroform (up to 86% ee) to aqueous DMF (up to 84% ee).

Letter from William Croswell to James [Lloyd], 1824 September 16

Draft of a letter chiefly concerning a proposal for a new edition of Croswell's Mercator map.

Bibliographical contributions from the Lloyd library, Cincinnati, Ohio.

2-3

Bibliographical contributions from the Lloyd library, Cincinnati, Ohio.

1

Letters from Michael Hogan to William Tudor,

Four letters discussing news of friends and domestic politics and the presidential election, in addition to trade and purchases of certain goods.

Letters from Michael Hogan to William Tudor,

Four letters regarding unrest in Chile, the election of Vice President Joaquín Vicuña and inception of the Chilean Civil War, and subsequent events related to the war.

Deed of feoffment for property in Cambridge, Massachusetts: from Thomas Sweetman to Michael Spencer, 1677 December 10

In this deed of feoffment, written on Dec. 10, 1677, Thomas Sweetman agreed to sell his dwelling house, barn, and orchard to his son-in-law, Michael Spencer, for the cost of eighty pounds sterling. The property was located in Cambridge, Massachusetts, on what was then the northwest corner of the grounds of Harvard College, and was sold "together with the wood lot upon the rocks and cow commons belonging to it." The deed specifies that both Sweetman and his wife Isabel were to be allowed to occupy the property until their deaths, and further explains that Spencer and his family were already living in the dwelling house, occupying three rooms. The document was signed, sealed, and delivered in the presence of Daniel Gookin, Jr. and John Bridgham. It was also signed by Thomas Sweetman.