Avinash N. Thadani

POTASSIUM ALLYL- AND CROTYLTRIFLUOROBORATES : STABLE AND EFFICIENT AGENTS FOR ALLYLATION AND CROTYLATION

Abstract Potassium allyl- and crotyltrifluoroborates react rapidly with aldehydes in the presence of BF 3 ·Et 2 O. These salts are stable to air and moisture, and lead to adducts in high yield and with high diastereoselectivity. The stereochemistry of the crotylated products is consistent with the reaction via allylboron difluoride and a Zimmerman-Traxler like transition state.

Allylation and Crotylation of Ketones and Aldehydes Using Potassium Organotrifluoroborate Salts under Lewis Acid and Montmorillonite K10 Catalyzed Conditions

Two convenient highly diastereoselective protocols for the allylation and crotylation of ketones using practical, air- and water-stable potassium allyl and crotyltrifluoroborate salts have been developed. BF(3).OEt(2) and montmorillonite clay are used as catalysts to promote additions. The montmorillonite-catalyzed method in particular is very robust, providing a straightforward and scalable method for the allylation and crotylation of a range of ketones and aldehydes.

Synthesis of benzylic mono(α,α-difluoromethylphosphonates) and benzylic bis(α,α-difluoromethylphosphonates) via electrophilic fluorination

Abstract A series of benzylic mono(α,α-difluoromethylphosphonates) and benzylic bis(α,α-difluoromethylphosphonates) have been prepared via electrophilic fluorination of the corresponding benzylic phosphonates.

Cross-coupling of aryl/heteroaryl bromides with ammonia using a copper-carbene catalyst

A variety of aryl and heteroaryl bromides were cross-coupled with ammonia in good to high yields in the presence of a copper-NHC catalyst.

Diastereoselective allylation and crotylation of N-unsubstituted imines derived from ketones

A wide variety of tertiary carbinamines are synthesized in high yields via diastereoselective allylation and crotylation of in situ generated N-unsubstituted ketimines.

Organoboron compounds as mild nucleophiles in Lewis acid- and transition metal-catalyzed C­C bond-forming reactions

The use of air- and water-stable organoboron compounds for CC bond-forming reactions are reported. These studies include the Lewis acid-promoted additions of boronic esters to N-acyliminium ions and allyl and crotyltrifluoroborate salts to aldehydes. Aryl and alkenyltrifluoroborate salts will add to aldehydes under the influence of rhodium catalysis or in the presence of zinc metal. These salts also participate in palladium-catalyzed SuzukiMiyaura and other cross-coupling reactions. Finally, a new type of N-heterocyclic carbene ligand is reported and used for Pd-catalyzed SuzukiMiyaura couplings.

Toxoplasma gondii: Inhibitory activity and encystation effect of securinine and pyrrolidine derivatives on Toxoplasma growth

Securinine, an alkaloid originally isolated from Securinega suffruticosa, exhibits a wide range of biological activities, including anti-malarial activity. Along with securinine, 10 pyrrolidine derivatives, generated via the retrosynthesis of (-)-securinine, were selected and tested for their inhibitory activity against Toxoplasma gondii growth in vitro. Anti-Toxoplasma activity correlated to hydrophobicity of the tested compounds. Three pyrrolidine derivatives along with securinine inhibit Toxoplasma proliferation at the micromolar range. These compounds act on parasite proliferation in different capacities, either by slowing the growth rate or inhibiting invasion of host cells. Securinine induces bradyzoite differentiation at comparable levels to treatment with alkali media in vitro.

Acyclic diaminocarbenes: simple, versatile ligands for cross-coupling reactions

Acyclic diaminocarbenes are found to be useful ligands for palladium catalyzed Suzuki-Miyaura, Sonogashira and Heck cross-coupling reactions of aryl/alkenyl bromides and chlorides.

Diels–Alder reactions of dienylboron compounds with unactivated dienophiles: an application of boron tethering for substituted cyclohexenol synthesis

An efficient tethered intramolecular Diels–Alder reaction of 1,3-dienylboronates with various allyl and homoallyl alcohols under thermal conditions is described.

2-(2-Cyclo­hex-1-enyl­vinyl)[1,3,6,2]­diox­aza­borocane

In the title compound, C12H20BNO2, the B—N distance is 1.6720 (17) A. Molecules are linked through intermolecular N—H⋯O hydrogen bonds to form infinite chains with an N⋯O distance of 2.8581 (13) A.