I. Noda

Synthesis of substituted tetrahydrofurans and tetrahydropyrans. 2. Stereocontrolled acid-catalyzed cyclizations

Abstract A new acid-catalyzed synthesis of thermodynamically stable 2,5-substituted tetrahydrofurans and 2,6-substituted tetrahydropyrans was developed in order to apply to the synthesis of complex polyether antibiotics.

Stereoselective synthesis of polyether antibiotics, lasalocid A and isolasalocid A, via a chelation-controlled formation of tetrahydrofuran rings under thermodynamic conditions☆

Abstract The B-rings (2,5-trans-tetrahydrofurans) of lasalocid A (6) and isolasalocid A (7) were stereoselectively constructed from the corresponding p-methoxyphenylallyl alcohols (13a, 13b) by treatment with ZnBr2 to give C13-C24 fragments (14a, 14b) via a new chelation-controlled cyclization under thermodynamic conditions. After their conversion into lasalocid ketone (19) and BOM-isolasalocid ketone (20), coupling with the C1-C11 aldehyde (22) completed the synthesis of 6 and 7, respectively.

Stereoselective total synthesis of polyether ionophore antibiotics, isolasalocid A and lasalocid A. part 1. stereocontrolled construction of the C rings (C18-C24) by acid-catalyzed cyclization of p-methoxyphenylallyl alcohols.

Abstract The C 18 -C 24 subunits ( 11, 12 ) of isolasalocid A ( 9 ) and lasalocid A ( 10 ) were synthesized stereoselectively via construction of the tetrahydrofuran and tetrahydropyran rings by acid-catalyzed cyclization of the corresponding p -methoxyphenylallyl alcohols ( 18, 25 ).

Stereoselective total synthesis of polyether ionophore antibiotics, isolasalocid A and lasalocid A. part 2. the total synthesis via stereoselective construction of the B rings by chelation-controlled cyclization under thermodynamic conditions.☆

Abstract Stereoselective total synthesis of isolasalocid A ( 1 ) and lasalocid A ( 2 ) was achieved via construction of the tetrahydrofuran rings by chelation-controlled cyclization of the corresponding p -methoxyphenyl substituted allyl alcohols ( 6, 7 ) under thermodynamic conditions.

Stereocontrolled syntheses of C18-C24 fragments of isolasalocid A and lasalocid A. An application of the acid assisted synthesis of functionalized tetrahydrofurans and tetrahydropyrans

The allyl alcohol (9) derived from D-glucose was easily cyclized by acid treatment and then converted to the C 18 -C 24 fragment (13) of isolasalocid A (5). Similarly, the allyl alcohol (15) derived from ethyl L-lactate was converted to the C 18 -C 24 fragment (20) of lasalocid A (6) via the tetrahydropyran derivative (16), which was kinetically formed by a chelation-controlled reaction