@article {49227,
	title = {Ready access to [5,6,5]-Trioxa-spiro and fused ketals via ag-catalyzed cascade annulation of 4-pentyn-1-ols and aldehydes},
	journal = {Organic Letters},
	volume = {26},
	year = {2024},
	month = {AUG},
	pages = {7116-7121},
	type = {Article},
	abstract = {<p>
	In this study, we unveil the versatility of 4-pentyn-1-ols as carbonyl surrogates for the unprecedented synthesis of diverse oxygen heterocycles, including [5,6,5]-bis-spiroketals (trioxadispiroketals) and [5,6,5]-furano-spiroketals related to bioactive natural products. These reactions commence with the pi-activation-induced intramolecular hydroalkoxylation of 4-pentyn-1-ols, yielding cyclic enol ethers, which undergo subsequent three-component annulation with aldehydes in a [2+2+1+1] fashion, resulting in the formation of [5,6,5]-bis-spiroketals. Notably, the distinctive steric features of alkynyl alcohols, particularly those with a secondary or tertiary alcohol functionality, dictate divergent reaction pathways, leading to the formation of [5,6,5]-furano-spiroketals.</p>
},
	issn = {1523-7060},
	doi = {10.1021/acs.orglett.4c02357},
	author = {Vinodkumar, Ramavath and Nakate, Ashwini K. and Gamidi, Rama Krishna and Kontham, Ravindar}
}
