1,062 research outputs found
Nathaniel P. Atkinson letter to Thomas Rotch, Estremedura, November 4th, 1814
No full textNathaniel Atkinson assures Thomas Rotch in Hartford that he is prepared to assume responsibility for his brother's debt and monies owed Rotch. The context of the letter is unclear. 8.5" x 9.8" (20.6 by 24.9 cm
Nathaniel P. Atkinson letter to Thomas Rotch, Wheeling, May 17th, 1817
No full textNathaniel Atkinson repeats that he is unable to repay a loan to Thomas Rotch because of business failures. He asks for an extension on the loan repayment, promising that he has every intention of repaying with interest. 8.5" x 9.6" (20.6 by 24.5 cm
Nathaniel P. Atkinson letter to Thomas Rotch, November 22nd, 1819
No full textNathaniel Atkinson inquires after cloth promised to him by Thomas Rotch who has neglected to respond in a timely manner. Atkinson, seemingly at the end of his rope with Rotch's failure to deliver his order, informs Rotch that he will not be able to sell the cloth this winter. 7.6" x 12.5" (19.4 by 31 cm
N.P. Atkinson letter to Thomas Rotch, Wheeling, June 21st, 1818
No full textNathaniel Atkinson took several of Thomas Rotch's merino breed sheep on lean and in this letter, he offers to sell Rotch some of his wool for processing in Rotch's factory at Kendal. Exchange was not unusual as hard currency was scarce and the banking system was unstable until at least 1823. 8.05" x 13" (20.6 by 32 cm
N.P. Atkinson letter to Thomas Rotch, Wheeling, February 11th, 1817
No full textNathaniel Atkinson reissues a fervent plea to Thomas Rotch for a loan of $300 to pay down his debts. He assured Rotch that when his wool comes in in the Fall he will be financially viable, but in the meantime, he remains in substantial difficulty, afraid of being sued and having his credit and good name ruined. 8.05" x 9.6" (20.6 by 24.3 cm
N.P. Atkinson letter to Thomas Rotch, Wheeling, July 22nd, 1816
No full textNathaniel Atkinson lays out terms for hiring out a portion of Thomas Rotch's Merino flock (and 100 Ewes)for three years. He specifies the breed of sheep he would prefer, the number of animals to be returned to Rotch in a year's time and also the amount of wool that he would return to Rotch in exchange for the animals to entrusted to his care. 7.6" x 9.62"(19.1 by 24.6 cm)on the reverse of this letter, Thomas Rotch noted that he accepted Atkinson's offer
Nathaniel P. Atkinson letter to Thomas Rotch, Wheeling, April 14th, 1816
No full textA note to Thomas Rotch about repayment of a loan. Atkinson informs Rotch that he intends to repay what is due and although currency was in limited supply, he has no intention of skipping his responsibility to Rotch. 8.12" x 6.2" (20.7 by 15.7 cm
N.P. Atkinson letter to Thomas Rotch, Wheeling, July 26th, 1815
No full textNathaniel Atkinson describes his low state of business as a consequence of the 1812 embargo that has left him with few resources. He mentions a debt owed to Thomas Rotch which he begs to be delayed if at all possible. 8.1" x 9.7" (20.6 by 24.5 cm
N.P. Atkinson letter to Thomas Rotch
No full textIn this undated letter, Nathanial Atkinson returns sheep numbering one hundred forty one or two animals loaned to him by Thomas Rotch. He requests that the bearer of the letter be reimbursed for expenses. Many persons who rented sheep from Rotch had little knowledge of the care and feeding of merinos and many animals were lost to predation by wolves and dogs. Rotch therefore recalled some of his sheep and successfully wintered over many animals with the addition of timothy and rye grass seeds to his pastures. 7.8" x 9.6" (19.8 by 24.5 cm
Mechanistic Investigations into the Palladium-Catalyzed Decarboxylative Allylic Alkylation of Ketone Enolates Using the PHOX Ligand Architecture
No full textPalladium-catalyzed asymmetric allylic alkylation has become a large and important field for chemical synthesis. Many methodologies in this field offer mild conditions under which challenging and important molecular features can be reliably synthesized, including chiral all-carbon quaternary stereocenters. As a result, palladium- catalyzed asymmetric allylic alkylation has found significant use in total synthesis, and growing use in industry. While the general process of palladium-catalyzed asymmetric allylic alkylation has been studied for decades, there have been a number of recent modifications and developments, such as asymmetric versions of decarboxylative allylic alkylation procedures that are not yet well understood. The development of future implementations and improvements to palladium-catalyzed asymmetric allylic alkylation and related methodologies is expected to be facilitated by a better understanding of these more recent developments, and thus further mechanistic investigation is warranted.
Reported herein is a set of investigations into the palladium-catalyzed decarboxylative asymmetric allylic alkylation of ketone enolates using the PHOX ligand architecture. By monitoring the reaction via 31P NMR, a series of previously unidentified key intermediates is discovered. Two representatives of these key intermediates are isolated and characterized. The solution behavior of these species under reaction-like conditions is studied along with a few novel and related complexes. The role of these intermediates and their impact on the behavior of the reaction and product formation is discussed. Previously confounding experimentally observed behavior for this methodology is rationalized via the properties elucidated for these discovered intermediates.</p
- …
