1.4- Dihydro-2,3-benzoxathiin 3-oxides

Synthesis of 1,4-dihydro-2,3-benzoxathiin 3-oxide as a useful precursor of o-quinodimethane The sultine l,4-dihydro-2,3-benzoxathiin 3-oxide 9 and substituted derivatives are ideal reagents for the in situ synthesis of o-quinodimethanes (o-xylylenes) 170 because they decompose smoothly in refluxing benzene at ca. 80°C and do not... 

Oxidation of freshly liberated 1,2,3,4-tetrahydrophthalazine (42) by mercury(II) oxide in the presence of sulfur dioxide gave an (unseparated) mixture of 1,4-dihydro-2,3-benzoxathiin 3-oxide (43) and l,3-dihydrobenzo[c]thiophene 2,2-dioxide (44) (substrate, CH2CI2, -20X, S02i, then HgOj, 20°C, 12h 45% of a 9 1 mixture in which the compounds were clearly identified). ... 

We have developed the efficient synthesis of the SERM drug candidate 1 and successfully demonstrated the process on a multiple kilogram scale to support the drug development program. A novel sulfoxide-directed borane reduction of vinyl sulfoxides was discovered. The mechanistic details of this novel reaction were explored and a plausible mechanism proposed. The sequence of asymmetric oxidation of vinyl sulfoxides followed by stereospecific borane reduction to make chiral dihydro-1,4-benzoxathiins was applied to the asymmetric synthesis of a number of other dihydro-1,4-benzoxathiins including the sweetening agent 67. 

Thermal decomposition of l,4-dihydro-2,3-benzoxathiin 3-oxides generates o-xylylenes which can be trapped by methyl 2-acetamidoacrylate yielding tetralin-based a-amino acids <04S558>. A phosphazene base [EtN=P(NMe2)2(N=P(NMe)2)3)] is used to generate the ylide from chiral oxathiane 74 in a two-step asymmetric synthesis of aziridines from tosylimines <04JOC1409>. 

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