Accelerated thermal reaction kinetics by indirect microwave heating of a microwave-transparent substrate

Macroscopically homogeneous mixtures of p-nitroanisole (pNA) and mesitylene (MES) can be selectively heated using microwave (MW) energy. The pNA solutes agglomerate into distinct phase domains on the attoliter-scale (1 aL = 10^-18 L), and these agglomerates can be MW-heated selectively to temperatures that far exceed the boiling point of the surrounding MES solvent. Here, a 1 : 20 mixture of pNA : MES is used as a mixed solvent for aryl Claisen rearrangement of allyl naphthyl ether (ANE). ANE itself does not heat effectively in the MW, but selective MW heating of pNA allows for transfer of thermal energy to ANE to accelerate rearrangement kinetics above what would be expected based on Arrhenius kinetics and the measured bulk solution temperature. This focused study builds on prior work and highlights 1 : 20 pNA : MES as a mixed solvent system to consider for strategically exploiting MW-specific thermal effects.

A Noncoordinating Acid-Base Catalyst for the Mild and Nonreversible tert-Butylation of Alcohols and Phenols

A mild and nonreversible tert-butylation of alcohols and phenols can be achieved in high yields using the noncoordinating acid-base catalyst [bis(trifluoromethane)sulfonimide and 2,6-lutidine] with a tert-butylation reagent, tert-butyl 2,2,2-trichloroacetimidate. This method allows the use of substrates containing acid sensitive groups such as ketal, Boc, and boronate esters.

Formation of DPM ethers using O-diphenylmethyl trichloroacetimidate under thermal conditions

Alcohols are effectively converted to their corresponding diphenylmethyl (DPM) ethers by reaction with O-diphenylmethyl trichloroacetimidate in refluxing toluene without the requirement of a catalyst or other additives. A number of acid and base sensitive substrates were protected in excellent yield using this new method without disturbing the pre-existing functionality present in these molecules. This reaction is the first example of the formation of an ether from stoichiometric amounts of a trichloroacetimidate and an alcohol without the addition of a Brønsted or Lewis acid catalyst.

Gold-catalyzed highly efficient benzylation of alcohols with N-Cbz-N-benzyl-propargylamine

Functional group tolerance under mild conditions eliminates the need for base additives or hygroscopic promoters.

Facile (triazolyl)methylation of MACOS-derived benzofused sultams utilizing ROMP-derived OTP reagents

A combination of MACOS scale-out and ROMP-derived oligomeric triazole phosphates (OTP(n)) have been successfully utilized for the preparation of a 106-member library of triazole containing benzothiaoxazepine-1,1-dioxides. This report demonstrates the utilization of a suite of soluble OTP(n) reagents for facile (triazolyl)methylation of 10 MACOS-derived sultam scaffolds in purification-free process for parallel synthesis of small molecule collections for HTS.