Masahiro Sakaitani

An efficient route to 1,3-amino hydroxyl system via electrophilic lactonization of 2-amino-4-pentenoic acid derivatives. Stereoselective synthesis of (−)-bulgecinine

Abstract Several γ-hydroxy-α-amino acid systems were prepared stereoselectively from 2-amino-4-pentenoic acid derivatives using electrophilic lactonization. This strategy was applied to the synthesis of a highly functionalized proline analogue, (−)-bulgecinine (4).

One-pot conversion of N-benzyloxycarbonyl group into N-tert-butoxycarbonyl group

Abstract An efficient one-pot two stage transformation of the N-Z group into the N- t -Boc group was carried out under the neutral conditions.

Synthesis of riccardin B by nickel-catalyzed intramolecular cyclization

Abstract Riccardin B, a macrocyclic bis(bibenzyl) possessing cytotoxic activity, and its dehydroxy derivative were synthesized in high yields using the nickel-catalyzed intramolecular coupling of the acyclic precursors.

A new mode of cyclic carbamate formation via tert-butyldimethylsilyl carbamate. Stereoselective syntheses of statine and its analogue

Abstract Stereoselective construction of 1,2- and 1,3-amino hydroxyl systems was carried out using S N 2′ (initiated by AgF or AgF-Pd(II)) cyclic carbamate formations from tert -butyldimethyl silyl carbamates. This method was applied to the syntheses of statine and AHPPA, efficiently.

N-carboxylate ion equivalent. II. Novel transformations of N-benzyloxycarbonyl (Z) group and N-allyloxycarbonyl group into N-t-butyldimethylsilyloxycarbonyl intermediate

Abstract N-Benzyloxycarbonyl compounds and N-allyloxycarbonyl compounds were efficiently converted to the corresponding t -butyldimethylsilyloxy-carbonyl compounds by t -butyldimethylsilane in the presence of Pd(II) catalyst.

New and efficient dehalogenative coupling and reduction of α-haloketones with active nickel complex. Facile syntheses of 1,4-diketones and bicyclo[4.2.O]oct-3-ene-2,5-diones

Abstract The active nickel complex generated in situ by reduction of NiBr2(PPh3)2 with zinc in the presence of Et4NI is a useful reagent for the dehalogenative coupling of phenacyl halides to 1,4-diaryl-1,4-diketones and for the dechlorination of 3,4-dichlorobicyclo[4.2.0]-octane-2,5-diones to bicyclo[4.2.0]oct-3-ene-2,5-diones.

Stereoselective hydroxylation of a peptide side chain. The synthesis of the echinocandin right-half equivalent

Abstract Highly stereoselective synthesis of the functionalized tripeptide 15a, equivalent to the echinocandin right-half 2, from the simple and rather symmetrical tripeptide 3 has been accomplished based on the halolactonization from the C-terminal of 3 and the cyclic carbamate formation from the N-terminal of 3.