Highly Enantioselective Oxidations of Ketene Dithioacetals Leading to Trans Bis-sulfoxides
作者:Varinder K. Aggarwal、Rebecca M. Steele、Ritmaleni、Juliet K. Barrell、Ian Grayson
DOI:10.1021/jo034032r
日期:2003.5.1
Sharpless-type asymmetric oxidation using (+)-DET, Ti(O(i)()Pr)(4), and cumene hydroperoxide to give the trans bis-sulfoxides 4a-f with essentially complete control of enantioselectivity and diastereoselectivity. The high enantioselectivity is a consequence of carrying out two asymmetric processes on the same substrate. However, this should lead to the formation of a small amount of the meso isomer but none was
Enolate Addition to a 2-Alkylidene[1,3]dithiane-Derived Bissulfoxide. A New a<sup>2</sup>-Acceptor
作者:Tobias Wedel、Joachim Podlech
DOI:10.1021/ol051670i
日期:2005.9.1
Reaction of enolates derived from esters and ketones to an easily prepared alkylidene[1,3]dithiane-1,3-dioxide afforded the respective adducts with good yields and selectivities generally exceeding 85:15. The base used for enolate addition played no significant role for the reaction outcome, and addition of a silyl enole ether gave similar results. The thus formed oxygenated S,S-acetals were transformed into the corresponding 1,4-dicarbonyls by a reduction/oxidation sequence with 84% yield.
NAGAO Y.; SENO K.; FUJITA E., TETRAHEDRON LETT., 1979, NO 45, 4403-4404