Cycloaddition mit ungesättigten Zuckern, I. Die 1,3‐dipolare Cycloaddition von Diphenylnitrilimin an α‐D‐ erythro ‐Hex‐2‐enopyranosid

Cycloaddition with Unsaturated Carbohydrates, I. — The 1,3‐Dipolar Cycloaddition of Diphenylnitrile Imine to α‐D‐ erythro ‐Hex‐2‐enopyranoside By 1,3‐dipolar cycloaddition of diphenylnitrile imine to ethyl 4,6‐di‐ O ‐acetyl‐2,3‐dideoxy‐α‐D‐ erythro ‐hex‐2‐enopyranoside ( 1 ) ethyl 4,6‐di‐ O ‐acetyl‐2,3‐dideoxy‐3′,4′‐dihydro‐2′,5′‐diphenyl‐2′ H ‐α‐D‐ menno ‐hexopyranosido[3,2‐ c ]pyrazole ( 2a ) and the [2,3‐ c ]‐regioisomer ( 3a; 2a: 3a = 4:1) were prepared.