A stereoselective synthesis of two epimeric polypropionate fragments with four adjacent chiral centers from 7-oxanorbornene derivatives

Building a Small Polypropionate Library. Synthesis of All Possible Stereotetrads (Building Blocks for Polyketide Synthesis) from Furan

“…These results made us move on to the second proposed approach . Epoxidation of 14 with lithium tert -butyl hydroperoxide followed by protection of the free hydroxyl group and reaction with MgBr 2 gave bromoketones 23 and 24 in a ratio 23 : 24 , 69:31 and 85% overall yield (Scheme ) .…”

Evolving Organic Synthesis Fostered by the Pluripotent Phenylsulfone Moiety

“…Thus, direct metalation of 45 in ether-hexane (tetrahydrofuran (THF) fails) provided the requisite enone 46 in a very respectable yield of 65% (Scheme 7). 31 Using the metalation-alkylation chemistry described in Scheme 7, the group of Mori has extensively studied the use of metalated R-epoxy sulfones analogous to 40 for alkylation of appropriately functionalized iodides and triflates. This study was part of a well-conceived intramolecular alcohol alkylation strategy for the synthesis of five-and sixmembered endocyclic R-alkoxy ketones.…”

“…The need for this reaction was revealed in a synthesis where conversion of 45 to α-bromoketone 47 was accomplished in 85% yield, but the subsequent elimination of 47 to enone 46 could only be realized in 32% yield. Thus, direct metalation of 45 in ether−hexane (tetrahydrofuran (THF) fails) provided the requisite enone 46 in a very respectable yield of 65% (Scheme ) …”

Advances in Synthesis of Enantioenriched Chiral Sulfones by Enantioselective Conjugate Addition Reactions

“…[12] And combining single crystal X-ray structure to furthur revealed the stacking structure of sulfones, the low energy conformations in the gas phase is connected into a butterfly conformation through intermolecular OÀ H alkyl and intramolecular OÀ H alkyl soft hydrogen bonding interaction, so as to keep the aromatic rings away from each other and minimize the spatial interaction. [12] Due to these distinct electronic and structural features, chiral sulfone groups can be converted to other functional groups through the simple alkylation, [13] oxidation, [14] desulfonation, [15,16] Julia olefinations [17] and so on. In recent decades, the synthesis and application of chiral sulfoxide are widely reported.…”