Temporary Silicon-Tethered Ring-Closing Metathesis Approach to C₂-Symmetrical 1,4-Diols:  Asymmetric Synthesis of d-Altritol

One‐Flask Tethered Ring Closing Metathesis–Electrocyclic Ring Opening for the Highly Stereoselective Synthesis of Conjugated Z/E‐Dienes

“…The strategy has been advantageously used, for example, with temporary silicon tethers, [36,37] to obtain acyclic alkenes Z-selectively, which cannot be achieved using standard cross metathesis reactions. [38] In contrast to other tethered RCM reactions, the carboxylate tether remains in the molecule after cleavage and serves as a valuable functional group.…”

Temporary Silicon–Tethered Ring–Closing Metathesis Reactions in Natural Product Synthesis

“…Evans and Murthy were the first to demonstrate the synthetic potential of silaketal intermediates in the TST-RCM with the construction of C 2 -symmetrical derivatives (Table 8.1) [13]. A series of enantiomerically enriched allylic alcohols were treated with dichlorodiphenylsilane and 2,6-lutidine to furnish the bis-alkoxysilane intermediates, which were subjected to RCM utilizing Grubbs' first-generation catalyst [Ru]-I, to provide the corresponding silaketals in excellent yield (entries [1][2][3][4][5].…”

“…The synthetic utility of this methodology was demonstrated with an application to a concise, total synthesis of the reduced carbohydrate d-altritol (Scheme 8.2) [13]. Dihydroxylation of the C 2 -symmetrical silaketal 3 with catalytic osmium tetroxide and N-methylmorpholine (NMO), followed by deprotection of the silyl ethers and peracetylation of the polyol to expedite isolation, furnished the hexaacetate 4 in 75% overall yield.…”

“…Ariza et al utilized the TST-RCM in conjunction with the Ireland-Claisen rearrangement to facilitate the total synthesis of (−)-phaseolinic acid (Scheme 8.3) [14]. The C 2 -symmetrical silaketal 6 was prepared in 58% overall yield using an adaptation of the protocol described by Evans and Murthy [13], which employed enantiomerically enriched propargylic alcohols to form the symmetrical bis-alkoxysilane rather than allylic alcohols. Selective reduction of the bis-alkyne with Lindlar catalyst, followed by RCM with catalyst [Ru]-I, afforded the silaketal 6 in good overall yield.…”

New cyclic and macrocyclic silaolefins via ring-closing metathesis of 1,1-bis(silyl)ethene-tethered dienes

“…Silicon-tethering ring-closing metathesis of dialkenyland dialkenyloxy-substituted compounds has been recently developed as a powerful tool for the enantioselective synthesis of symmetrical diols [26], polyols [27] and a wide range of natural products [28][29][30].…”