01532nas a2200157   4500008004100000022001400041245008900055210006900144260000800213300001600221490000700237520097100244100002601215700002201241856011101263       2022                        eng d  a0022-326300aConcise total synthesis of (+)-lanceolactone a: revision of absolute stereochemistry0 aConcise total synthesis of lanceolactone a revision of absolute   cOCT  a12867-128760 v873 a<p>
	A chiral-pool protecting-group-free five-step total synthesis of tetranorsesquiterpenoide (+)-lanceolactone A and all of its four stereoisomers using (S)-(+)-, and (R)-(-)-linalool (coriandrol) as building blocks is disclosed. The key steps involved in this synthetic route are regioselective ozonolysis, Au(I)-catalyzed cycloisomerization-induced construction of furan from alleneone, and dye-sensitized photo-oxidation (through O-1(2) ; singlet oxygen) of hydroxyalkyl-tethered furan to access oxaspirolactone. After a thorough evaluation of electronic circular dichroism (ECD) and optical rotation data of all possible stereoisomers, the absolute configuration of natural lanceolactone A at the C4 and C7 positions has been assigned as (+)-(4S,7S), which is an enantiomer to the initially proposed structure (+)-(4R,7R). Further, these investigations led us to extend Feringa and Gawronski's CD correlation method to [5,5]- and [6,5]-oxaspirolactones.</p>
1 aBorade, Balasaheb, R.1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/concise-total-synthesis-lanceolactone-revision-absolute-stereochemistry