Room temperature DBN initiated phospha‐Brook rearrangement of α‐hydroxyphosphonates to phosphates

A series of substituted aryl phosphate esters have been synthesized from their α‐hydroxyphosphonates substrates, using DBN (1,5 diazabicyclo(4.3.0)non‐5‐ene) at room temperature, via a phospha‐Brook rearrangement. The aryl‐substrate dependence of the rearrangement was explored, and excellent yields of the phosphate esters were achieved irrespective of whether the aryl moiety was activated or unactivated. A plausible mechanism for the rearrangement has been proposed. Based on the low temperature 31P‐NMR, the mechanism of the phospha‐Brook rearrangement is proposed to take place via an oxaphosphirane intermediate

Ketone Hydrosilylation with Sugar Silanes Followed by Intramolecular Aglycone Delivery: An Orthogonal Glycosylation Strategy

Gettin' a little sugar—no alcohol required : A procedure for the direct glycosylation of ketones without a hydroxy intermediate enables the site-selective glycosylation of hydroxyketones at the ketone or the alcohol functionality without the use of protecting groups on the aglycone (see scheme). Site selectivity is controlled by the catalyst structure in hydrosilylation and dehydrogenative silylation reactions with sugar silanes. Bn=benzyl.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63086/1/anie_200901666_sm_miscellaneous_information.pd