Naofumi Tsukada

Synthesis and crystal structure of twisted dinuclear η3-allylpalladium complexes containing tetradentate nitrogen ligands

Abstract The dinuclear palladium allyl complexes 7 and 12, which contain tetradentate nitrogen ligands 2 or 3 as bridging ligands, respectively, were synthesized and characterized. Crystal X-ray analysis of these complexes reveal that the two coordination planes of the palladium are twisted, although each of the coordination spheres presents roughly the same structural features as the related (bipyridine)allylpalladium complex.

Palladium-catalyzed [2+2] cycloaddition of allylic acetates and norbornene

Abstract Palladium-catalyzed reaction of norbornene with allyl acetate gave 3-methylenetricyclo[4.2.1.02,5]nonane 1 and 2-methylene-3-vinylnorbornane 2 in high yields. The substituents on allyl acetate strongly influenced the selectivity. In the reactions of 1- or 3-substituted allyl acetates, cycloadducts corresponding to 1 were obtained exclusively. Use of methallyl acetate gave solely a diene corresponding to 2.

Palladium-catalyzed allylic alkenylation of allylic alcohols with n-butyl acrylateElectronic supplementary information (ESI) available: spectral data for compounds 1, 2, 4, and 5. See http://www.rsc.org/suppdata/cc/b3/b307705e/

Various allylic alcohols reacted with n-butyl acrylate in the presence of p-toluenesulfonic anhydride and palladium catalysts to yield the corresponding n-butyl 2,5-dienoates with high regioselectivity.

Asymmetric synthesis of the β-lactam framework via a three-component coupling reaction

The reaction of the chiral lithium amide 4 with the dienoate 5a provides regio- and stereo-selectively the β-amino ester 8 in essentially quantitative yield with >99% diastereoisomeric excess, which can be converted upon sequential treatment with LiNPri2–B(OMe)3–MeCHO to the key intermediate 6 for the β-lactam 7 having the correct absolute configuration.

Highly stereocontrolled and concise asymmetric synthesis of the β-Lactam framework via a TCC method

Abstract The conjugate addition of LSA 1 to t-butyl (4S)-4-(trityl)oxy-2-pentenoate 2d followed by aldol condensation with acetaldehyde produces a key intermediate 3 to β-lactam derivatives as a single diastereoisomer in 77 % yield.

INTER- AND INTRAMOLECULAR PALLADIUM-CATALYZED HYDROCARBONATION OF METHYLENECYCLOPROPANES WITH CARBON PRONUCLEOPHILES

Abstract The inter- and intramolecular additions of pronucleophiles to methylenecyclopropanes proceeded smoothly in the presence of catalytic amounts of Pd(PPh3)4, affording hydrocarbonation products in good to high yields. The ring opening of methylenecyclopropanes mainly occurred at the distal position to the exomethylene. In some cases, proximal bond cleavage also took place. The mode of ring opening depended upon both the structure of the pronucleophile and the substituent at the exomethylene carbon.

Regio- and stereo-selective ring opening of epoxides with amide cuprate reagents

Amide cuprate reagents attack the less hindered carbon atom of epoxides to give 1,2-amino alcohols in good yields; this procedure is applied to the synthesis of an aziridine alcohol bearing a carborane framework which is a potentially useful 10B carrier for boron neutron capture therapy.

Palladium-catalyzed 1,6- and 1,5-diyne-carbon monoxide reaction for preparation of alkylidenecyclopentenones and -butenolides

Carbonylative [2+2+1] cycloaddition of 1,6-diyne under carbon monoxide at atmospheric pressure catalyzed by Pd2(dba)3-PPh3-CF3SO3H presents a new approach to the formation of a bicyclo[3.3.0]octa-1,5-dien-3-one ring system. Under higher pressure the reaction of 1,6- and 1,5-diynes occurred in a different fashion via tandem insertion of carbon monoxide to yield alkylidenebutenolide.

Rhodium-catalyzed allylation of styrenes with allyltosylate

Rhodium-catalyzed allylation of styrene with allyl tosylate gave 1-phenylpenta-1,4-diene, and various styrene derivatives were also allylated yielding 1,4-dienes or 1,5-dienes.

PALLADIUM CATALYSED ALKYLATIVE DIMERIZATION BETWEEN PRONUCLEOPHILES AND VINYLTINS

In the presence of catalytic amounts of Pd 2 (dba) 3 ·CHCl 3 and dppb, the reaction of pronucleophiles 1 with vinyltins 2 gives the corresponding alkylative dimerization products of the vinyl group, 1,4-disubstituted butene derivatives 3, in good to high yields.