Syntheses of all the stereoisomers of butanol type 1,7-seco-2,7′-cyclolignane

All the stereoisomers of butanol type 1,7-seco-2,7 '-cyclolignane were stereoselectively synthesized by employing (S)- and (R)-Evans' auxiliaries to construct the stereochemistry. (+)- and (-)-Kadangustin J and their diastereomers were also prepared. The optical purity of the synthesized butanol type 1,7-seco-2,7 '-cyclolignane was more than 99%ee.