Enantioselective Michael addition of isobutyraldehyde to nitroalkenes organocatalyzed by chiral primary amine-guanidines

Primary amine-guanidines derived from trans-cyclohexane-1,2-diamines are used as organocatalysts for the enantioselective conjugate addition of isobutyraldehyde to arylated and heteroarylated nitroalkenes. The reaction was performed in the presence of imidazole as the additive in aqueous DMF as the solvent at 0 °C. The corresponding Michael adducts bearing a new stereocenter were obtained in high yields and with enantioselectivities of up to 80%. Theoretical calculations are used to justify the observed sense of the stereoinduction.

Enantioselective Michael addition of aldehydes to maleimides organocatalysed by chiral 1,2-diamines: an experimental and theoretical study

Simple and commercially available chiral 1,2-diamines were used as organocatalysts for the enantioselective conjugate addition of aldehydes, including α,α-disubstituted, to maleimides. The reaction was carried out in the presence of hexanedioic acid as an additive in aqueous solvents at room temperature. By employing (1S,2S)- and (1R,2R)-cyclohexane-1,2-diamine as organocatalysts, the corresponding Michael adducts bearing new stereocenters were obtained in high or quantitative yields with enantioselectivities of up to 92%, whereas the use of (1S,2S)-1,2-diphenylethane-1,2-diamine gave a much lower ee. Theoretical calculations were used to justify the observed sense of the stereoinduction.

Enantioselective Synthesis of Succinimides by Michael Addition of Aldehydes to Maleimides Organocatalyzed by Chiral Primary Amine-Guanidines

The monoguanylation of (1S,2S)- and (1R,2R)-cyclohexane-1,2-diamine affords chiral primary amine-guanidines that are used as chiral organocatalysts in the enantioselective Michael addition of aldehydes, particularly α,α-disubstituted aldehydes, to maleimides. The reaction is carried out in the presence of imidazole, as an additive, in aqueous N,N-dimethylformamide, as the solvent, and affords the corresponding enantioenriched succinimides in high or quantitative yields with enantioselectivities up to 96 % ee. Theoretical calculations (DFT and M06–2X) suggest a different hydrogen-bonding coordination pattern between the maleimide (C=O) and the catalyst (NH groups) is responsible for the enantioinduction switch that is observed when the reaction is carried out using primary amine-guanidines versus primary amine-thioureas as the organocatalysts.

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).

Payment order for Josiah Cotton, 1722 September 10

Handwritten order to Penn Townsend to pay scholarship funds to student Josiah Cotton (Harvard AB 1722), signed by Benjamin Wadsworth, Thomas Foxcroft, Samuel Marshall, and Jonathan Williams.

Accounts with Harvard College, 1719-1722

The thin paper-covered notebook contains the Steward's accounts with Harvard College kept by Steward Andrew Bordman II from 1719-1722. Arranged by quarters, the entries list money collected by the Steward from students, and money paid for food supplies, household provisions, the Butler's salary, and for services provided to the College.

Bond between John Leverett and Edward Hutchinson, Treasurer of Harvard College, 1722 June 13

One-folio sized leaf containing a handwritten copy of a bond between John Leverett and Edward Hutchinson, Treasurer of Harvard. The bond was witnessed by Benjamin Walker and John Edwards, Jr. An October 3, 1726 receipt of payment from Nathaniel Byfield on the bond, signed by Treasurer Edward Hutchinson, is located on the verso of the first leaf.

The Report of the Committee appointed to Consid'n of the Memorial of the Overseers of Harvard College, 1722 June 29

Two folio-sized leaves containing a handwritten copy of a June 29, 1722 report created by a Committee of the General Court responding to the June 13, 1722 memorial of the Board of Overseers. The report lists three points declaring that the Charter of 1650 intended the Tutors to be members of the Corporation "provided they exceed not five in number," that none of the Fellows be Overseers, and that the Charter of 1650 did not grant the Corporation the power to set salaries without the consent of the Overseers. The copy notes that the report was read and accepted on June 29, and signed by Governor Samuel Shute on July 2, 1722, with the stipulation that none of the current non-resident Fellows be removed from the Corporation.

Quarterly account book, 1722-1751

The quarterly accounts are held in one tall folio volume spanning the years 1722-1751. The volume contains three sections: a journal of quarterly accounts tallying money owed to the Butler by students and tutors, followed by a journal of purchases made by the Butler, and finally, written tête-bêche (from the back cover forward), a ledger with weekly calculations and final quarterly sums owed the Butler by students and tutors.

Tutor Sever's Final Argument, 1722

This marbled hardcover volume contains a forty-one-page handwritten draft of the memorial from Nicholas Sever to the Harvard Board of Overseers providing a historical background on the College charters. The document begins, "May it please ye Excell: of ye Coll: to fav'r me w'th a few words for ye further support of this memorial." The draft includes struck-through words and page 41 contains directions for additional edits.