A little cooperation goes a long way: The cooperative Brønsted/Lewis acid-base supramolecular catalysts formed in situ from simple chiral magnesium(II) binaphtholate aqua complexes promoted the highly enantioselective 1,4-hydrophosphinylation of α,β-unsaturated esters with diaryl phosphine oxides and 1,2-hydrophosphonylation of α,β-unsaturated ketones with dialkyl phosphites (see scheme).

We report on the spectroscopy and photodynamic characterization of Brønsted and Lewis acid sites within solids with respect to the behavior of Nile Red (NR) upon interaction with single- and multi-metal(X)-doped MCM41 materials (X = Ti and/or Al) in dichloromethane (DCM) suspensions. The steady-state results show that the H-bonding ability of doped MCM41-based materials leads to different NR po...

0021-9517/$ see front matter 2009 Elsevier Inc. A doi:10.1016/j.jcat.2009.03.005 * Corresponding author. Fax: +1 510 642 4778. E-mail address: [email protected] (E. Iglesia). We describe here a rigorous method to estimate the deprotonation energy (DPE) and acid strength for solid Brønsted acids with uncertain structure using rate constants for reactions involving cationic transition states. ...

H/D exchange observed between bridging hydroxyl groups in acidic zeolite ZSM-5 and adsorbed acetone (acetone-d6/H-ZSM-5 and 13C-2-acetone/D-ZSM-5) indicates a concerted catalytic function of Brønsted acid sites and neighbouring framework oxygen atoms acting as Lewis base sites.

An efficient and practical synthesis of triaryl and trisindolylmethanes is reported via the bisarylation of aryl aldehydes with activated arenes. The new method features mild solvent-free reaction conditions, in most cases nearly stoichiometric reagent ratios, catalytic amount of the readily available, easily-handled, recoverable and reusable Brønsted acid catalyst o-benzenedisulfonimide.

An enantioselective Brønsted acid catalyzed Mannich reaction between acetophenone derived enamines and N-Boc imines has been developed. Simple diol (S)-H(8)-BINOL has been identified as the optimal catalyst, to afford versatile beta-amino aryl ketones in good yield and enantiomeric excess.

A versatile and highly enantioselective chiral Brønsted acid-catalyzed allenylation of aldehydes with propargyl borolane is reported. The reaction is shown to be practical and quite general with a broad substrate scope covering aryl, heteroaryl, α,β-unsaturated, and aliphatic aldehydes.

A novel, one-pot allylboration-Heck reaction of 2-bromobenzaldehydes has been developed for the general and efficient synthesis of 3-methyleneindan-1-ols. Modification of the one-pot procedure to include chiral Brønsted acid catalyzed allylation has allowed the preparation of these building blocks in high enantioselectivity and excellent yields.