Hiroto Harayama

Pd2+-catalyzed oxidative aminocarbonylation of O-2,3-butadienyl and O-3,4-pentadienyl N-tosylcarbamates

Abstract Pd 2+ -catalyzed aminocarbonylation of O -2,3-butadienyl 1 and O -3,4-pentadienyl carbamates 5 stereoselectively provides 4-(1-methoxycarbonylviny])-1,3-oxazolidin-2-ones 2 and 4-(1-methoxy-carbonylvinyl)-1,3-oxazin-2-ones 6 , respectively, in high yields.

Chemoselective intramolecular aminocarbonylation of unsaturated amides under Wacker-type conditions

Abstract The Wacker-type aminocarbonylation of unsaturated amides shows distinctive dependence of reactivity on the reaction medium: endo nitrogen nucleophiles ( endo -carbanates 3 and -ureas 5 ) undergo aminocarbonylation either in neat methyl orthoacetate (MOA) or in methanol containing AcONa and MOA, while exo nitrogen nucleophiles ( exo -carbamates 1a , -ureas 1b , and -sulfonamides 1c ) in methanol (cat. PdCl 2 , stoichiometric CuCl 2 under 1 atm of CO). The generality is indicated by the chemoselective transformations of 7a-d either into 8a-d in MOA or into 9a-d in methanol.

Selective reaction of π-allyl(alkyloxy)palladium(II) complexes toward β-decarbopalladation, β-dehydropalladation, and reductive elimination

Abstract Depending on the kind of R 1 and R 2 , cyclic carbonates 1 , in the presence of 10 mol% of Pd(PPh 3 ) 4 and 10 equiv of paraformaldehyde, selectively undergo three types of reaction: 1 (R 1 , R 2 ≠ H) give dienes 3 exclusively; 1 (R 1 = R 2 = H and R 1 ≠ H, R 2 = H) furnish 6-vinyl-1,3-dioxanes 5 exclusively, while 1 (R 1 = H, R 2 ≠ H) give rise to 4-pentenyl formates 4 selectively (together with 3 as the minor products).

Highly regio-, stereo-, and chemoselective Diels–Alder reaction of monothiomaleimide, an ambident C S and C C dienophile

The thiocarbonyl group of monothiomaleimide 1 serves as a more reactive dienophile than the electron-deficient CC double bond in the same molecule for the Diels–Alder reaction with dienes 2c–g and provides ortho-endo products 3 exclusively or predominantly over the other possible adducts 4–10.

Palladium(II) catalysed 5-endo-trigonal cyclization of 2-hydroxybut-3-enylamines: synthesis of five-membered nitrogen heterocycles

2-Hydroxybut-3-enylamines 1 undergo a novel PdII-catalysed 5-endo-trigonal cyclization to provide pyrrolines 2, pyrroles 3, and/or 3-oxopyrrolidines 4 in good to moderate combined isolated yields; the hydroxy group is essential for the cyclization.

Pronounced electronic effects of the allylic amino group on the π-facial stereoselectivity and reactivity in electrophilic additions to double bonds

The selectivity of iodoetherification of N-substituted 3-aminopent-4-en-1-ols 1, providing mixtures of N-substituted (E)-and (E)-3-amino-2-iodomethyltetrahydrofurans [(Z)-2 and (E)-2], correlates well with the electronic effects of the N-substituents, increasing with an increase in the electron withdrawing effect of the substituents.