Induction of a preferred sense of twist in flexible diphenyls by carbohydrate scaffolds. Synthesis of two "naked" ellagitannin analogous.
The synthesis of "naked" ellagitannin analogues 1 and 2, having a preferred sense of twist of the diphenyl moiety, with a rhamnose and a glucose template, is reported. A clear induction in the chirality of the diphenyl moiety, mediated through a 10-membered ring via ester linkages, was observed. The chiral scaffold of glucose (diequatorial 2,3-hydroxyl groups) exerts a remarkable stronger atropdiastereoselective effect onto the diphenoyl group than the rhamnose ring (axial-equatorial 2,3-hydroxyl groups), according to the Schmidt-Haslam hypothesis.
Capozzi
G
G
Centro CNR Chimica e Struttura dei Composti Eterociclici, Dipartimento di Chimica Organica, Universita' di Firenze, Via G. Capponi, 9 I-50121 Florence, Italy.
Ciampi
C
C
Delogu
G
G
Menichetti
S
S
Nativi
C
C
D001713:Biphenyl Compounds / Q000737:chemistry*; D002241:Carbohydrates / Q000737:chemistry*; D002942:Circular Dichroism; D047348:Hydrolyzable Tannins; D007202:Indicators and Reagents; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013634:Tannins / Q000138:chemical synthesis*
D001713:Biphenyl Compounds; D002241:Carbohydrates; D047348:Hydrolyzable Tannins; D007202:Indicators and Reagents; D013634:Tannins; C013515:ellagitannin