Fig. 4: Synthetic transformations.

a Pd-catalyzed Negishi cross-coupling of 4a and alkyl zinc reagent. b Pd-catalyzed Negishi cross-coupling of 4a and aryl zinc reagent. c Pd-catalyzed Sonogashira cross-coupling of 4a and aryl alkyne. d Phosphonation reaction of 4a via in situ axially chiral lithium intermediate.