Reactions of [H<INF>2</INF>Os<INF>3</INF>(CO)<INF>10</INF>] with Conjugated Diynes (RC<INF>2</INF>C<INF>2</INF>R‘) Containing Nucleophilic Oxygen in β Position of a Substituent (R = Ph, R‘ = CH<INF>2</INF>OH, C(O)Ph; R = R‘ = CMe<INF>2</INF>(OH))

Reactions of [H<INF>2</INF>Os<INF>3</INF>(CO)<INF>10</INF>] with a series of diynes, RC<INF>2</INF>C<INF>2</INF>R‘ (<BO>1</BO>:  R = Ph, R‘ = CH<INF>2</INF>OH; <BO>2</BO>:  R = Ph, R‘ = C(O)Ph; <BO>3</BO>:  R = R‘ = C(OH)Me<INF>2</INF>), have been studied. It was found that upon coordination to the triosmium cluster, the nucleophilic oxygens of the R‘ substituents of <BO>1</BO> and <BO>2</BO> take part in intramolecular cyclization reactions to give [HOs<INF>3</INF>(CO)<INF>10</INF>{μ-η¹:η²-PhCH<INF>2</INF>(C&dbd;CH−C&dbd;CH−O)}] (<BO>5</BO>) and [HOs<INF>3</INF>(CO)<INF>10</INF>{μ-η¹:η¹-Ph(C&dbd;CH−C&dbd;C−O)CPh}] (<BO>6</BO>), respectively, both of which contain furan rings coordinated to the cluster core. On heating of the latter compound, the furan moiety remains intact, but a carbonyl group dissociates from the cluster, leading to the formation of [HOs<INF>3</INF>(CO)<INF>9</INF>(μ<INF>3</INF>-η¹:η³:η¹-Ph(C&dbd;CH−C&dbd;C−O)CPh)] (<BO>7</BO>) with a closed “C<INF>3</INF>Os<INF>3</INF>” pentagonal pyramidal structure. Reaction of [H<INF>2</INF>Os<INF>3</INF>(CO)<INF>10</INF>] with <BO>3</BO> does not lead to cyclization of the diyne; instead, the clusters [Os<INF>3</INF>(CO)<INF>10</INF>{μ<INF>3</INF>-η²-(RCH&dbd;CH−C<INF>2</INF>R)}] (<BO>8</BO>) and [Os<INF>3</INF>(CO)<INF>10</INF>{μ<INF>3</INF>-η²-(RC<INF>2</INF>C<INF>2</INF>R)}] (<BO>9</BO>) are formed. Deuterium labeling of the starting compounds has been used in the reaction of [H<INF>2</INF>Os<INF>3</INF>(CO)<INF>10</INF>] with HOCH<INF>2</INF>C<INF>2</INF>C<INF>2</INF>CH<INF>2</INF>OH in order to investigate possible mechanisms of the cyclization reaction. The crystal and molecular structures of clusters <BO>5</BO>,<BO> 7</BO>, and<BO> 9</BO> are presented.