James R. Hauske

A SOLID PHASE CBZ CHLORIDE EQUIVALENT : A NEW MATRIX SPECIFIC LINKER

Abstract Treatment of TentaGel S resin (1) with phosgene provides matrix linked chloroformate (2), which is converted to the corresponding carbamoylated derivatives 3a and 3b. Alternatively, Wang resin provides the imidazolide (7a), which is readily transformed to amides and esters by treatment with nitrogen and carbon nucleophiles, respectively.

Formation of CC bond in solid phase synthesis using the heck reaction

Abstract The palladium promoted vinylation of aryl iodide bound to a solid support was studied. Under the reaction conditions of water/DMF/Pd(OAc) 2 /PPh 3 /base, the reaction proceeds smoothly and leads to moderate to high yield of product at 37°C after 4–18 hours.

Preparation and reactions of chiral propargylic amines

Abstract Exposure of chiral amino aldehydes ( 1 ) to dimethyl diazophosphonate ( 4 ) affords propargylic amines ( 2 ) of high optical purity. Chain extension of these intermediates is readily accomplished via hydrozirconation of the acetylene moiety and subsequent Ni(II) catalyzed Michael addition to a variety of Michael acceptors.

Synthesis of non-peptide scaffolding domains via a totally stereoselective iodolactonization protocol

Abstract Exposure of the chiral, non-racemic, allylic ester 7 to LDA/MSCl provides acid 8 and subsequent iodolactonization of 8 provides one lactone ( 9 ) with total stereoselectivity. X-ray analysis of the corresponding α-methylbenzylamides of 8 and 9 confirmed the absolute stereochemistry of the trans-anti-trans lactone ( 9 ). The synthesis is completed by treatment of 9 with the enolate of t-butyl acetate affording tetrahydrofuranyl derivative 12 .

1.3 – Organoaluminum Reagents

Organoaluminums have been reviewed extensively. The first thorough treatise was published in 1972 by Mole,1 describing the preparation of organoaluminums and their reactions with various functional groups. Negishi2,4 and Yamamoto3 have also reviewed the general properties and reactions of organoaluminums. However, Negishi2 focused on the 1,2-nucleophilic additions of α,β-unsaturated organoaluminums, which specifically included the reactions of alkenylalanes and alkenylalanates with carbon electrophiles, whereas the Yamamoto review3 was of a more general nature. The preparation of alkenyl- and alkynyl organoaluminums has also been reviewed by Normant5 and Zweifel.6 The portion of the Normant review that focused on organoaluminum reagents described the syn specific carbometallation of alkynes by organoaluminums, which provides stereospecific access to alkenylaluminums. In contrast, Zweifel6 prepared a very detailed review dealing with the preparation and reactions of alkenyl- and alkynyl-aluminums.